Dunno, lets the player just get on with their rehab without any pressure because no one knows what the injury is? Maybe some players just want to keep it private.
possibly, but it does seem to be across the board these days.
in ice hockey it's not uncommon for a team to say that a player has "a lower body injury" and leave it at that - the idea being that when he's back playing, you don't want oppo teams to target his (left leg or whatever) when they are slamming into him and put him out again.
doesn't translate to football though.