A player being told he can't play the rest of the season because of a (possibly covid-related) heart condition is a big emotional blow. If the heart damage is bad enough, could be even be career-ending. This might be one of those times that a reporter would want to be a little sympathetic and give the player time to process the bad news, and wait for the go-ahead from the player to be ok with releasing the info.
Secondly, why give UNC the news ahead of time? Let them think Blades is playing and gameplan for that. This "breaking news" isn't going to move the needle any more on a Monday than it would on Saturday morning before the game.