The major objective of this chapter is to elaborate on the importance of comprehensive assessment and development of a robust grading system to identify concussion and to predict athletes at risk for brain re-injury due to premature return to sport participation. There is a growing body of knowledge accumulating in the literature and in clinical practice indicating the danger of long-term residual dysfunctions in athletes suffering from even single mild traumatic brain injury. It should be noted that several position statements elaborated by the mutual effort of numerous prominent leaders in this field have been recently proposed. These documents in general, and my contribution to this book, in specific, may assist team physicians, athletic trainers and coaches in providing optimal care for athletes who have sustained a concussion. So, possible long-terms abnormalities should not be overlooked while assessing brain injured athletes at the site of injury and monitoring these athletes during their course of recovery. Overall, to accomplish this goal, the medical professionals shouldhave knowledge of and be involved with epidemiology, pathophysiology, evaluation/and treatment, post game-day evaluation/and treatment, diagnostic imaging, management principles, return-to-play criteria, complications of concussion, and prevention. Most importantly, one must understand that an athlete, while still symptomatic at either rest or exertion should not be allowed to return to competition. No athlete who has experienced loss of consciousness or amnesia should be allowed to go back into the event that same day. The general tenor is “if in doubt, sit them out. Additional factor that need to be considered is the athlete’s total concussion history; including the number and the severity of those prior concussions. Moreover, the temporal proximity of concussions and the severity of the blow causing the concussion need to be assessed. Minor blows causing serious concussions should make a physician more hesitant to return an athlete to competition. The exact mechanisms of both short term_and long lasting abnormalities in the brain’s functional, behavioral, cognitive abilities and many other overseen abnormalities as a result of concussion in athletes still remains to be elucidated. This chapter is complementary to other chapters in this book to fully realize the ongoing controversies and problems with evaluation and treatment of sport-related traumatic brain injuries.