Numerous other Big10 schools are saying they're not seeing this in their athletes that have tested positive for COVID-19.
https://saturdaytradition.com/big-ten-football/report-multip...
https://saturdaytradition.com/big-ten-football/report-multip...
There has been at least one confirmed case among MLB players[1]. It is also interesting to note that this cites a 10-20% number for the occurance of myocarditis among people with COVID-19.
[1] - https://www.espn.com/mlb/story/_/id/29579222/boston-red-sox-...