“Patur, Rav Moshe does not say which of ball game he is referring. Baseball? Not so dangerous. Perhaps football? In Israel, the English-speakers’ yeshivot have their own league. Are exercise and letting off steam matirim?”
He is referring to something which is ??? ???? ????? ?????? ???? ???? ????? ?????? and something which is ?????? ??? ???? ????? ????
Now his Teshuva is specifically talking about ??????? ????? ?????
??????? which would seem to imply that if it’s not ??????? then it would be assur (unless there is some other hechrech on par with parnassa which would allow you to engage in an activity with a small risk of sakanna).