Kim and colleagues, representing the American College of Cardiology's Sports and Exercise Council, published recommendations 1 for the evaluation of athletes who had tested positive for COVID-19 to ensure safe return to play.The group recommended a tiered approach based on the presence of symptoms, followed by electrocardiography (ECG), injury biomarkers, and echocardiography. Abnormalities were then to be further characterized by the selective use of cardiac magnetic resonance (CMR) imaging. The recommendations were based on expert opinion of experienced sports cardiologists, because there were at the time only modest data to inform such a document. A report 2 on 26 college athletes who were asymptomatic or had only mild symptoms found CMR evidence of myocarditis in 4 (15%). Both the Kim et al report 1 and our Editorial 3 at the time called for larger data sets, so that recommendations could be refined and more informed by data.In only 6 months since then, there has been a remarkable amount of information acquired, analyzed, and published regarding post-COVID-19 prevalence of cardiac abnormalities in athletes, as summarized in the Table. 2,[4][5][6][7][8][9][10][11] In a recent study of 789 professional athletes, screening consisted of serum troponin testing, ECG, and echocardiography, regardless of symptoms. 8 Thirty of these athletes (3.8%) had abnormal test results resulting in referral for CMR imaging, with 3 diagnosed with myocarditis. Similarly, in a large cohort of 3018 college athletes from 42 universities, 9 a strategy using serum troponin tests, ECG, and echocardiography identified 15 athletes (0.5%) with possible cardiac involvement. In a subgroup of 198 athletes in that report 9 who underwent a primary CMR imaging-based screening strategy (ie, without selection by the other tests), a higher proportion of athletes demonstrated definite, probable, or possible cardiac involvement (n = 6 [3.0%]).In the current issue of JAMA Cardiology, a study by Daniels et al 11 adds substantially to the extant information. As they note, starting in September 2020, the Big Ten athletic conference (involving 13 major universities) mandated comprehensive cardiac screening, including ECG, troponin testing, echocardiography, and CMR imaging for athletes in the aftermath of positive COVID-19 test results, regardless of prior symptomatic status. The authors report on a large sample of 2461 athletes, of whom 1597 (64.9%) had the complete comprehensive screening testing, including CMR imaging without prior selection. They found that 37 (2.3%) of these athletes demonstrated diagnostic criteria for myocarditis by CMR imaging, including 20 without cardiovascular symptoms and with normal ECG, echocardiography, and troponin test results, who