Injuries are considered an inevitable by-product of participation in elite sport (Hurley et al., 2007), and over the past 30 years, psychologists have proposed a number of models to explain athletes' psychological reactions to their injuries. These models have included the grief model (Kubler-Ross, 1969; Rotella, 1988) and the cognitive appraisal models (Brewer, 1998; Wiese-Bjornstal et al., 1998). When examining the value of these models, researchers have identified a number of factors mediating athletes' responses to their injuries. Factors such as social support (Clement and Shannon, 2011) and perceived consequences of injuries for the athletes (Hurley et al., 2007) have been popular lines of investigation. A less popular avenue of research has been the impact of tournament-ending injuries on the mental states of remaining squad members called upon to perform without their injured colleagues. Given the lack of research in this area, it could be fruitful to discuss the potential impact of player attrition rates on their teams' mental states, and subsequent performances, using the Rugby World Cup 2015 (RWC 2015) as a case study. This case study is considered appropriate because many countries suffered serious injuries to some of their best players just before, or during, this RWC (Lewis, 2015). For example, the Irish team lost one of its most experienced players, Paul O'Connell, due to injury early in the tournament, as did South Africa, who was forced to play without captain, Jean De Villiers, from game three of the tournament. Similarly, the New Zealand “All Blacks” lost their experienced player, Tony Woodcock, due to injury before their quarter final match. Despite the loss of Woodcock, the New Zealand team was successful in defending its RWC title from 2011. Indeed in 2011, New Zealand played without four of its out-half players. Is it possible the New Zealand team did something different, compared to the other nations, to prepare successfully for both the RWC 2011 and 2015 tournaments? This paper will explore possible reasons why some of the other nations failed to perform to their potential at the RWC 2015. This paper is organized as follows: First, the mental challenges team players may have faced following the loss of influential players through injury will be discussed. The potential for emotional contagion to have permeated throughout such teams, and its possible impact on those teams' subsequent performances will dominate this discussion (Moll et al., 2010). Second, some possible areas for future research will be suggested, focusing on the role support staff (including coaches, medical staff, and sport psychologists) working with such teams might play in helping their teams to thrive in such circumstances in the future.