Not to say I'm an expert on the way people talk and they way they sound, but when Damon says "Oh yeah, I forgot about that" he didn't sound like it was a grave situation, but rather like 'oh yeah i forgot about that no biggie'.
Plus, there are numerous reasons a player may not be on campus atm and we should not rush to think this is a bad thing. It could be, but we don't know. If he was kicked off the team we'd know because every other player that leaves, gets suspended, etc., is reported on and told to the media.
My guess is it is either something small or a suspension that really isn't a big deal. He also might be ill.
tl;dr If it was bad like getting cut from the team or a suspension, we would know.