Free Agents Research Articles

DEA와 SFA 모형을 이용한 한국 프로야구의 비용효율성 분석

The purpose of this study is to analyze the cost efficiency of Korean professional baseball(KBO) teams through Data Envelopment Analysis(DEA) and Stochastic Frontier Analysis(SFA) and to examine its determinants.. In this study, we used 20 years of data from 2003 to 2022 for eight teams to examine the cost efficiency and its influencing factors of each team through DEA window analysis and SFA reflecting the time series. The empirical results showed that the cost efficiency of KBO teams is not high, but it is generally improving. Among them, the size of the stadium and the number of wins have a positive effect on cost efficiency, while the number of new stadiums and free agents has a negative effect on cost efficiency. In particular, the difference between the efficiency values derived from the two methods is quite large, which means that it is highly sensitive to external shocks due to the probable error. The fact that many teams react greatly to external shocks suggests that the support of parent companies and local governments greatly affects the sustainability of the teams due to the lack of self-reliance of the teams. In order to increase the self-reliance of KBO teams facing a new competitive environment after COVID-19, continuous efforts are needed to transform into solid companies, including positive external support and cooperation with local governments, as well as creating higher-quality cultural content and discovering diverse sources of revenue.

Ability to do otherwise, reasons, and causes

AbstractWhat does it tell us about the compatibility of freedom and determinism to recognize that, while acting freely, we typically have good reasons for whatever we are doing? More than it seems, I suppose. In this paper, it is argued that two well‐established accounts of human freedom—libertarianism and local miracle compatibilism—understate the connection between reasons and actions, leaving us only with the causal part of the explanation. This is so because on the basis of these views, a majority of alternate actions relevant for the ascription of the ability to do otherwise turn out to be either unreasonable or irrational. Hence, by denying that free agents possess an ability to do otherwise rationally, these accounts fail to provide an adequate characterization of free action. Then, it is shown that the necessary requirement of reasons‐responsiveness may be satisfied by the altered‐reasons analysis of the ability to do otherwise. This particular kind of multiple‐past compatibilism, while providing a plausible response to the incompatibilist argument, also corresponds to a version of conditional analysis that is resistant to the classical objections to desire‐, choice‐, or try‐based conditionalism.

Pulmonary Protective Effects of Vitamin D and N-Acetylcysteine on Paraquat-Induced Lung Toxicity in Rats: Modulation of Oxidant / Antioxidant Balance

Background: Paraquat (PQ) is one of the most common herbicides used in agriculture that can lead to very acute toxicity in mammals. It has been reported that PQ has destructive effects on the lungs. Objective: We aimed to investigate the effect of N-acetyl Cysteine (NAC) and Vitamin D (Vit D) on the oxidative toxicity of the lung in subacute paraquat exposure. 36 male albino Wistar rats at 8 weeks were randomly divided into 6 groups (n=6). A control group, a PQ-intoxicated group (5 mg/kg body weight), a Vit D-treated group (2 μg/kg), an NAC-treated group, a PQ (6.25 mg/kg) + Vit D group, and finally a PQ + NAC group, each was treated for 7 days. Methods: In this experimental study, Lipid Peroxidation (LPO), Total Oxidant Status (TOS), Total Antioxidant Capacity (TAC), Total Thiol Groups (TTG), and Hydroxyproline (Hyp) levels in lung tissue were evaluated. Results: PQ exposure resulted in a substantial elevation of LPO, TOS, and Hyp levels. Conversely, TAC and TTG content demonstrably declined. Administration of either PQ+Vit D or PQ+NAC significantly reduced LPO, TOS, and Hyp levels in the PQ-exposed rats compared to the PQ group alone. Conversely, TAC and TTG content significantly increased in these groups. These findings suggest that both vitamin D and NAC may function as free radical scavengers and potential antioxidant agents, potentially alleviating the detrimental effects of PQ poisoning on the lungs. Conclusion: The present study has demonstrated the administration of Vit D and NAC to significantly mitigate PQ-induced lung injury in rats. This protective effect can be likely attributed to their modulation of the oxidant/antioxidant balance, as evidenced by reductions in LPO, TOS, and Hyp levels, alongside increases in TAC and TTG content. These findings suggest that vitamin D and NAC may function as free radical scavengers and antioxidant enhancers, offering protection against PQ-induced oxidative stress and subsequent lung tissue damage.

Carcinomembrane-Camouflaged Perfluorochemical Dual-Layer Nanopolymersomes Bearing Indocyanine Green and Camptothecin Effectuate Targeting Photochemotherapy of Cancer.

Photochemotherapy has been recognized as a promising combinational modality for cancer treatment. However, difficulties such as off-target drug delivery, systemic toxicity, and the hypoxic nature of the tumor microenvironment remain hindrances to its application. To overcome these challenges, cancer cell membrane camouflaged perfluorooctyl bromide (PFOB) dual-layer nanopolymersomes bearing indocyanine green (ICG) and camptothecin (CPT), named MICFNS, were developed in this study, and melanoma was exploited as the model for MICFNS manufacture and therapeutic application. Our data showed that MICFNS were able to stabilize both ICG and CPT in the nanocarriers and can be quickly internalized by B16F10 cells due to melanoma membrane-mediated homology. Upon NIR irradiation, MICFNS can trigger hyperthermia and offer enhanced singlet oxygen production due to the incorporation of PFOB. With ≥10/2.5 μM ICG/CPT, MICFNS + NIR can provide comparable in vitro cancericidal effects to those caused by using an 8-fold higher dose of encapsulated CPT alone. Through the animal study, we further demonstrated that MICFNS can be quickly brought to tumors and have a longer retention time than those of free agents in vivo. Moreover, the MICFNS with 40/10 μM ICG/CPT in combination with 30 s NIR irradiation can successfully inhibit tumor growth without systemic toxicity in mice within the 14 day treatment. We speculate that such an antitumoral effect was achieved by phototherapy followed by chemotherapy, a two-stage tumoricidal process performed by MICFNS. Taken together, we anticipate that MICFNS, a photochemotherapeutic nanoplatform, has high potential for use in clinical anticancer treatment.

A Study on News Frame Related to Free Agent Issue of Professional Baseball Player in the Media

A Study on News Frame Related to Free Agent Issue of Professional Baseball Player in the Media

Antitumoral activity of a CDK12 inhibitor in colorectal cancer through a liposomal formulation

Colorectal cancer (CRC) is the third most common cancer worldwide. Recent experiments suggest that CDK12 can be a good therapeutic target in CRC, and therefore, novel inhibitors targeting this protein are currently in preclinical development. Lipid-based formulations of chemical entities have demonstrated the ability to enhance activity while improving the safety profile. In the present work, we explore the antitumor activity of a new CDK12 inhibitor (CDK12-IN-E9, CDK12i) and its lipid-based formulation (LP-CDK12i) in CRC models, to increase efficacy. SW620, SW480 and HCT116 CRC cell lines were used to evaluate the inhibitor and the liposomal formulation using MTT proliferation assay, 3D invasion cultures, flow cytometry, Western blotting and immunofluorescence experiments. Free-cholesterol liposomal formulations of CDK12i (LP-CDK12i) were obtained by solvent injection method and fully characterized by size, shape, polydispersity, encapsulation efficiency, and release profile and stability assessments. LP-CDK12i induced a higher antiproliferative effect compared with CDK12i as a free agent. The IC50 value was lower across all cell lines tested, leading to a reduction in cell proliferation and the formation of 3D structures. Evaluation of apoptosis revealed an increase in cell death, while biochemical studies demonstrated modifications of apoptosis and DNA damage components. In conclusion, we confirm the role of targeting CDK12 for the treatment of CRC and describe, for the first time, a liposomal formulation of a CDK12i with higher antiproliferative activity compared with the free compound.

Synthesis, characterization, and molecular docking studies of novel hippuric acid anhydrides as potential antiurolithic, analgesic and free radical scavenging agents

Hippuric acid is a biotransformation product in humans which is excreted through urine. Dietary intake of phenolic compounds increases its concentration in urine. Hippuric acid is experimentally proved to be a regulator of calcium oxalate super saturation in human urine and has a solvent effect on oxalate salts. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used analgesics employed in associated renal colic of urolithiasis. The objective of the present study was to chemically link hippuric acid through anhydride linkage to various NSAIDs to synthesize potential mutual prodrugs for urolithiasis and associated renal colic. Hippuric acid was linked to eleven NSAIDs through anhydride linkage by first synthesizing hippuryl chloride using oxalyl chloride as chlorinating agent, followed by its reaction with sodium salts of NSAIDs. Structures of obtained compounds were elucidated using UV spectrophotometry, FTIR spectrometry, 1H NMR and C-13 NMR spectrometry. Synthesized compounds were evaluated for in vitro antioxidant, in vivo acute toxicity, in vivo antiurolithic, in vivo analgesic and in vitro hydrolysis studies. Molecular docking analysis on TNF-α and COX-2 was carried out to determine target protein binding. Synthesized compounds showed stability at acidic pH which indicate potential gastro protective effect of synthesized conjugates. Compounds P9 an P6 showed maximum in vivo antiurolithic activity while P9 and P8 showed maximum in vitro antioxidant activity. All the conjugates except P2 showed significant analgesic activity which show that conjugation of hippuric acid to NSAIDs did not result in loss of analgesic potential. Docking studies showed better affinity with TNF-α as compared to COX-2.

Iron protoporphyrin IX-hyaluronan hydrogel-supported luminol chemiluminescence for the detection of nitric oxide in physiological solutions

Due to its role as a free radical signal-transducing agent with a short lifespan, precise measurement of nitric oxide (●NO) levels presents significant challenges. Various analytical techniques offer distinct advantages and disadvantages for ●NO detection. This research aims to simplify the detection process by developing a hydrogel system using iron(III)-protoporphyrin IX (hemin)-loaded hyaluronan for the detection of ●NO in solution. Various hydrogel formulations were created, and the effects of their components on hydrogel-supported luminol chemiluminescence (CL) kinetics, radical scavenging, and physicochemical properties were analysed through factorial analysis. The candidate formulations were then evaluated using two ●NO donors. An increase in the degree of crosslinking in unloaded formulations enhanced interactions with the CL reaction components, hydrogen peroxide (H2O2) and luminol, thereby affecting light generation. However, hemin loading negated these effects, resulting in more prominent luminescence kinetics in formulations with lower crosslinking degrees. Similarly, ●NO influenced the kinetics differently, interacting with both the CL reaction and hydrogel components. Hemin-loaded formulations exhibited enhanced signal propagation when exposed to ●NO, followed by H2O2 and luminol, whereas reversing the order of addition inhibited this propagation. The magnitude of these luminescence changes depended on the type and concentration of the ●NO donor, demonstrating greater sensitivity to ●NO levels compared to amperometric sensing. These findings suggest that the studied hydrogel platform has potential for the facile and accurate detection of ●NO in solution, requiring minimal sample sizes.

Compensating wage differentials: Evidence from the National Hockey League

Using data for 1,471 unrestricted free agent player contracts in the NHL, this paper finds evidence that players are willing to sacrifice earnings to play on a higher quality team, and this tradeoff increases with player age. This result, which is consistent with the theory of compensating wage differentials, is robust to multiple specifications and estimation methodologies.

The effect of the initial distribution of labor-related property rights on the allocative efficiency of labor markets

IntroductionThe Coase Theorem posits that frictionless markets efficiently allocate scarce resources as long as property rights are fully specified. Our empirical study investigates how the initial allocation of labor-related property rights influences the allocative efficiency in labor markets for skilled workers within a highly competitive environment—professional basketball. Specifically, we compare two regimes: one where employers can trade workers to other employers without the worker's consent, and another where workers are free agents, able to negotiate and move freely without their employer's consent.MethodsWe utilize the NBA as a “laboratory” to conduct our analysis, constructing a unique panel dataset that includes 3,132 player-season observations spanning 17 regular seasons from 2003/04 to 2019/20. To address our research question, we employ linear panel regression models to analyze the data.Results and discussionThe findings reveal a decline in productivity among workers who transition to new employers as free agents, a phenomenon not observed among non-free agents. This observation suggests that allocative efficiency might be higher when workers are traded without their consent compared to when they exercise their autonomy as free agents. These findings highlight the significant impact that the initial distribution of labor-related property rights has on labor market efficiency, potentially challenging the assumptions of the Coase Theorem. However, the lack of a statistically significant difference in productivity changes between free agents and non-free agents moving to new employers prevents us from definitively rejecting the predictions of the Coase Theorem.

Building Flame-Retardant Polymer Electrolytes via Microcapsule Technology for Stable Lithium Batteries.

Flame retardants could improve the safety properties of lithium batteries (LBs) with the sacrifice of electrochemical performance due to parasitic reactions. To concur with this, we designed thermal-response clothes for hexachlorophosphazene (HCP) additives by the microcapsule technique with urea-formaldehyde (UF) resin as the shell. HCP@UF combines with polyacrylonitrile (PAN) by hydrogen bonds successfully to form PAN-HCP@UF as the flame-retardant solid polymer electrolyte. The hydrogen bonds ensure excellent mechanical properties of the polymer electrolyte. The multiscale free radical-annihilating agent HCP effectively eliminates hydrogen free radicals of electrolytes under high temperature, showing excellent flame retardation. During the operation of the battery, functional groups on the UF resin act as active sites to promote the migration of lithium ions, while the internal HCP is protected from electrochemical reaction. With 25% HCP@UF addition, the limiting oxygen index of the PAN-HCP@UF increases to 28% and the Li+ transfer number up to 0.80. By UF protection, the initial capacity retention rate of the Li||LFP battery that assembles with PAN-HCP@UF is 88.8% after 500 cycles at 0.5 C. Thus, the microcapsule-encapsulated approach is deemed to provide an innovative strategy to prepare high-safety solid-state LB with a stable long cycle life.

Spatial separation of photocarriers and selective adsorption on flower-like core-shell heterojunction of Cr(VI) imprinted polymer@BiOI for boosted photocatalytic Cr(VI) reduction

BackgroundConstructing heterojunction photocatalyst is a well-established strategy for enhancing photocatalytic Cr(VI) reduction due to the heightened separation and transfer of photocarriers. Whereas, aimless and random transfer of photocarriers and low photocarrier utilization rate deriving from the weak interface interaction between heterojunction and Cr(VI) are still limited the photocatalytic reduction performance of Cr(VI). MethodsHerein, a flower-like core-shell heterojunction photocatalyst was designed by wrapping a pyridine-based Cr(VI) imprinted polymer (PCIP) onto flower-like BiOI to achieve spatial separation of photocarriers and selective adsorption of Cr(VI), resulting in an outstanding photocatalytic reduction performance of Cr(VI). Significant findingsIn the core-shell heterojunction, photocarriers could be spatially separated, and then brought about high-efficient photocatalytic Cr(VI) reduction close to the selective adsorption sites of Cr(VI). After measurement, the optimal PCIP@BiOI core-shell heterojunction, polymerized for ≈30 min, exhibited a robust photocatalytic reduction performance of Cr(VI), without adding any free radical sacrifice agents. Within 1 h, the aqueous solution containing 100 mg/L of Cr(VI) could be completely removed, and the photocatalytic reduction rate constant of Cr(VI) was ≈20 times superior to BiOI. This study presents a methodology for designing core-shell heterojunction photocatalysts on the basis of inorganic/organic conjunction for environmental remediation of high concentrations of Cr(VI).

Chemically engineered mTOR-nanoparticle blockers enhance antitumour efficacy

Hepatocellular carcinoma (HCC) is a highly prevalent and deadly type of cancer, and although pharmacotherapy remains the cornerstone of treatment, therapeutic outcomes are often unsatisfactory. Pharmacological inhibition of mammalian target of rapamycin (mTOR) has been closely associated with HCC regression. Herein, we covalently conjugated AZD8055, a potent mTORC1/2 blocker, with a small panel of unsaturated fatty acids via a dynamically activating linkage to enable aqueous self-assembly of prodrug conjugates to form mTOR nanoblockers. Cell-based experiments were carried out to evaluate the effects of the nanoblocker against hepatocellular carcinoma (HCC) cells. The orthotopic and subcutaneous HCC mouse models were established to examine its antitumour activity. Among several fatty acids as promoieties, linoleic acid-conjugated self-assembling nanoblocker exhibited optimal size distribution and superior physiochemical properties. Compared with free agents, PEGylated AZD8055 nanoblocker (termed AZD NB) was pharmacokinetically optimized after intravenous administration. Invivo investigations confirmed that AZD NB significantly suppressed tumour outgrowth in subcutaneous HCCLM3 xenograft, Hepatoma-22, and orthotopic Hepa1-6 liver tumour models. Strikingly, treatment with AZD NB, but not free agent, increased intratumour infiltration of IFN-γ+CD8+ T cells and CD8+ memory T cells, suggesting a potential role of the mTOR nanoblocker to remodel the tumour microenvironment. Overall, a single conjugation with fatty acid transformed a hydrophobic mTOR blocker into a systemically injectable nanomedicine, representing a facile and generalizable strategy for improving the therapeutic index of mTOR inhibition-based cancer therapy. The mTOR inhibition by chemically engineered nanoblocker presented here had enhanced efficacy against tumours compared with the pristine drug and thus has the potential to improve the survival outcomes of patients with HCC. Additionally, this new nanosystem derived from co-assembling of small-molecule prodrug entities can serve as a delivery platform for the synergistic co-administration of distinct pharmaceutical agents. This work was supported by the National Natural Science Foundation of China (32171368,81721091), the Zhejiang Provincial Natural Science Foundation of China (LZ21H180001), the Jinan Provincial Laboratory Research Project of Microecological Biomedicine (JNL-2022039c and JNL-2022010B), State Key Laboratory for Diagnosis and Treatment of Infectious Diseases (zz202310), and Natural Science Foundation of Shandong Province (ZR2023ZD59).

The case for neuregulin-1 as a clinical treatment for stroke.

Ischemic stroke is the leading cause of serious long-term disability and the 5th leading cause of death in the United States. Revascularization of the occluded cerebral artery, either by thrombolysis or endovascular thrombectomy, is the only effective, clinically-approved stroke therapy. Several potentially neuroprotective agents, including glutamate antagonists, anti-inflammatory compounds and free radical scavenging agents were shown to be effective neuroprotectants in preclinical animal models of brain ischemia. However, these compounds did not demonstrate efficacy in clinical trials with human patients following stroke. Proposed reasons for the translational failure include an insufficient understanding on the cellular and molecular pathophysiology of ischemic stroke, lack of alignment between preclinical and clinical studies and inappropriate design of clinical trials based on the preclinical findings. Therefore, novel neuroprotective treatments must be developed based on a clearer understanding of the complex spatiotemporal mechanisms of ischemic stroke and with proper clinical trial design based on the preclinical findings from specific animal models of stroke. We and others have demonstrated the clinical potential for neuregulin-1 (NRG-1) in preclinical stroke studies. NRG-1 significantly reduced ischemia-induced neuronal death, neuroinflammation and oxidative stress in rodent stroke models with a therapeutic window of >13 h. Clinically, NRG-1 was shown to be safe in human patients and improved cardiac function in multisite phase II studies for heart failure. This review summarizes previous stroke clinical candidates and provides evidence that NRG-1 represents a novel, safe, neuroprotective strategy that has potential therapeutic value in treating individuals after acute ischemic stroke.

Free Agent Migration in the Korean Professional Baseball League: To Move or Not to Move

Abstract: This study explores free agent transactions of the Korea Baseball Organization from 2000 to 2018. It examines whether player mobility patterns differ across free agent pitchers and hitters. The probability of free agent pitchers transferring increases with the pitching position of the starting or closer pitcher. The probability of transfer for a hitter is negatively associated with age and left-handedness. The inertia of staying with the current team increases when substantial signing bonuses are paid to the free agent pitcher. A strong contract year affects the hitter mobility model, with a higher probability of transfer and a greater contribution to team wins in the final year before free agency. The longer a free agent’s contract, the higher the probability of them moving. A huge increase in the annual salary one year before free agent eligibility hinders the movement of hitters, whereas financial compensation does not constrain pitchers’ move.

Does It Hurt Financially, Too? Effects of Injury Proneness on Contract Design in Major League Baseball

Abstract: This paper seeks to determine the financial costs of recent injuries and market expectations of players’ future attrition rates by investigating the impacts on free agent contract designs, as represented by the yearly salary and contract length. The empirical findings, derived from data about 698 free agent contracts in Major League Baseball between 2011 and 2018, indicate that injuries exert different impacts on salaries versus contract lengths. For example, free agents who recently injured an elbow or shoulder receive shorter contracts than those not injured in the previous season, but their salaries are not affected. Market expectations of player attrition in the upcoming season reduce both contract lengths and salaries. For players, these results reaffirm the importance of staying healthy and finding ways to signal the low likelihood of future injuries to ensure their remuneration. For managers, the results emphasize the need to track free agents’ health status carefully, especially to avoid a winner’s curse.

‘He seems to be at the back of all the stories’: The Subtlety of Narnian Providence

Towards the end of The Horse and His Boy, as Shasta wanders blindly into Narnia, he unknowingly encounters Aslan, who explains to him the various ways that Aslan has watched over him dating back even to the boy’s infancy. It is a beautiful account of Aslan’s care for Shasta. If one were to focus exclusively on this passage, however, one might conclude that Narnian providence is merely a matter of external divine intervention and that creaturely agency plays little role in the way Aslan governs Narnia. An analysis of some of Lewis’s non-fictional writings in conversation with Thomas Aquinas uncovers a more subtle understanding of providence. For Lewis, as for Aquinas, providence incorporates the acts of free agents without compromising their integrity. Virtuous, indifferent, and even vicious acts all contribute in some way to God’s plan for the universe. The same can be said for Narnia, as one can see through representative examples from The Silver Chair, The Horse and His Boy, and The Magician’s Nephew. In these stories Lewis illustrates, to paraphrase his own words about Oedipus Rex, ‘how providence and free will can be combined, even how free will is the modus operandi of providence’.

A T-Cell Inspired Sonoporation System Enhances Low-Dose X-Ray-Mediated Pyroptosis and Radioimmunotherapy Efficacy by Restoring Gasdermin-E Expression.

Genome editing has the potential to improve the unsatisfactory therapeutic effect of antitumor immunotherapy. However, the cell plasma membrane prevents the entry of almost all free genome-manipulation agents. Therefore, a system can be spatiotemporally controlled and can instantly open the cellular membrane to allow the entry of genome-editing agents into target cells is needed. Here, inspired by the ability of T cells to deliver cytotoxins to cancer cells by perforation, an ultrasound (US)-controlled perforation system (UPS) is established to enhance the delivery of free genome-manipulating agents. The UPS can perforate the tumor cell membrane while maintaining cell viability via a controllable lipid peroxidation reaction. In vitro, transmembrane-incapable plasmids can enter cells and perform genome editing with the assistance of UPS, achieving an efficiency of up to 90%. In vivo, the UPS is biodegradable, nonimmunogenic, and tumor-targeting, enabling the puncturing of tumor cells under US. With the application of UPS-assisted genome editing, gasdermin-E expression in 4T1 tumor-bearing mice is successfully restored, which leads to pyroptosis-mediated antitumor immunotherapy via low-dose X-ray irradiation. This study provides new insights for designing a sonoporation system for genome editing. Moreover, the results demonstrate that restoring gasdermin expression by genome editing significantly improves the efficacy of radioimmunotherapy.

Fucoidan coated liposomes loaded with novel antituberculosis agent: preparation, evaluation, and cytotoxicity study

In this article, we described a novel antituberculosis imidazotetrazine derivative designed in fucoidan-coated liposomes to reduce its cytotoxicity and investigate its mucoadhesive properties. Firstly, fucoidan extracted from Ascophyllum nodosum was used for additional stabilization of liposomal suspensions and to give it mucoadhesive properties. PEG-600 and/or Tween-80 were used to increase the shelf life of liposomal suspension. The ratio of the fucoidan: lipids 1:2 was found to be the optimum that produces stable fucoidan-coated liposomes. The particle size of the optimum formulation was 336.3 ± 5.4, the PDI was 0.33, and the zeta potential was −39.6. This size and the practical spherical shape of the particles were confirmed by atomic force microscopy. In addition, the in vitro release profiles from uncoated and fucoidan-coated liposomes revealed significant and faster release compared to free antituberculosis agent. Using the MTT assay test, the fucoidan-coated liposomes exhibited fourteen times lower cytotoxicity (IC50 7.14 ± 0.91 µg/ml) than the free drug (IC50 0.49 ± 0.06). Moreover, the mucoadhesive capabilities of these liposomal formulations were also confirmed using snail mucin, which highlighting their potential use as an effective delivery system for antituberculosis therapy, with notable improvements in dissolution rate and reduced cytotoxicity.

Strategic behaviours in a labour market with mobility-restricting contractual provisions: evidence from the National Hockey League

Abstract We follow workers’ performance along an unbalanced panel dataset over multiple years and study how performance varies at the end of fixed-term contracts, in a labour market where some people face a mobility-restricting clause (i.e. a noncompete clause). Focusing on the labour market of the National Hockey League, we analyse players’ performance data and contracts with a fixed-effects estimator to address empirical limitations in previous studies. We find that, on average, National Hockey League players’ performance does not vary. However, our estimations detect substantially heterogeneous behaviours, depending on tenure, perceived expected performance, and mobility. Only younger players (i.e. restricted free agents) with high expected mobility but low expected performance tend to behave strategically and perform better. Differently, older players (i.e. unrestricted free agents) with high expected mobility tend to underperform, as the option of moving back to European tournaments is more appealing.