ABSTRACT Extant research has characterised various group behaviours through the lens of the theory of subjective group dynamics, which describes how ingroup members’ deviation from the group’s prescriptive norms can impact other members’ perceptions of the group and its members. Deviations from ingroup norms may result in the black sheep effect, which refers to the tendency for individuals to actively judge deviant ingroup members more harshly than similar behaving outgroup members. In this study, we examined the black sheep effect in the context of sports fans’ judgments about athletic performance. When athletes violate sports fans’ prescriptive team norms by performing poorly, these fans may derogate such athletes. Subjective group dynamics in sports contexts has been understudied, and findings for the black sheep effect have been mixed. Thus, we empirically tested for these phenomena in two experiments using fictitious cases of ingroup and outgroup athlete performances. In line with predictions from subjective group dynamics, we found a lack of ingroup bias on perceived competence and increased identity threat following poor performance, with team identification moderating such outcomes in Study 1. Although the presence of the black sheep effect was not confirmed in Study 2, our second experiment offers evidence to suggest that fans may equate poor-performing, ingroup athletes with similar outgroup players. Limitations and future directions for research are discussed.