Clinical Scenario: Ulnar collateral ligament (UCL) injuries are highly prevalent in professional baseball players with the success of operative management being well known in the literature. Return to play (RTP) rates following nonoperative management of partial UCL injuries in professional baseball players are not well established in the literature. With a UCL tear being a potential career-ending injury, it is imperative that the best treatment option is provided to these throwing athletes. There is an increase in the incidence of UCL surgical rates and a lack of general agreement on nonoperative treatment of partial UCL injuries as reported by the American Shoulder and Elbow Surgeons in 2017. There is also a lack of clarity on when to initiate rehabilitation, which may be due to the limited amount of studies reporting success of RTP rates and time to RTP following conservative interventions of partial UCL injuries. Evidence on the RTP rates seen following conservative management of partial UCL tears injuries can help guide health care providers in deciding on the best treatment option for professional baseball athletes who desire to return to their athletic careers. These rates of RTP will add valuable objective input when determining if conservative management is the best choice. To determine the current evidence, inclusion criteria for the literature search consisted of RTP rates following conservative treatment in professional baseball players between inception and 2018. Clinical Question: Is there evidence for successful RTP rates in professional baseball players following conservative treatment of a UCL injury? Summary of Key Findings: Three retrospective studies met the inclusion criteria and were included. Of those, 2 reported RTP rates following a nonoperative rehabilitation program of a UCL injury, whereas 1 reported RTP rates after injection therapy in subjects who attempted a trial of conservative treatment. All 3 studies considered location and grade of UCL tear. Successful RTP rates (66%-100%) were reported in professional baseball players following nonoperative treatment of partial UCL injuries. Clinical Bottom Line: Current evidence supports high success with RTP rates up to 100% after nonoperative treatment of grade 1 UCL injuries in professional baseball players and between 66% and 94% for a grade 2 and above. Strength of Recommendation: There is level C evidence for high RTP rates following nonoperative treatment of partial UCL injuries in professional baseball players.