Since Junior-to-Senior Transition (JST) is only considered successful when soccer players become professionals, many junior athletes must cope with failure, and their sporting careers and mental health may be at risk. Therefore, the objectives of this study are to (a) identify different career expectancies of male soccer academy players, and (b) describe irrational beliefs, perfectionism and mental health levels associated with different career expectancies, identifying risk factors in the JST. A total of 515 male soccer players between 14 and 19 years old (M = 16.7; SD = 1.6) who played in Spanish professional youth academies during the 2020–2021 season, answered questionnaires on sports career model, beliefs, perfectionism and mental health (i.e., iPBI, MPS-2 and GHQ-12). The results suggest that the number of juniors who aspire to be professionals (57%) far exceeds the number of players who become professionals (10%; Dugdale in Scandinavian Journal of Medicine & Science in Sports 31:73–84, 2021). Also, results show that this population presents high levels of demandingness (M = 5.5), low frustration tolerance (M = 5.2), self-organization (M = 5.2) and social functioning (M = 5.5), and low scores on depreciation (M = 2.6) and loss of confidence and self-esteem (M = 2.4). In a more detailed way, the results are compared according to expectancies. These academies are usually environments where success and failure are antagonistic concepts, and where perfectionism and irrational beliefs are normalized and integrated among all members of this context. However, the possible maladaptive effects put their mental health at risk. With the aim of rationalizing the concepts of success and failure and protecting their mental health, especially those who will not become professionals, this study proposes a new route based on the REBT philosophy and ARRC technique.