Back in the 2008 All-Star Game at Yankee Stadium, it was said early in the broadcast that Tim Lincecum was unavailable due to a hospitalization for "flu-like symptoms". A friend of mine who knew someone who used work for the Phillies with close access to the clubhouse told me that "flu-like symptoms" was baseball jargon/public coverup for too hungover to play.
He was only 19 games into his major league career though. If someone already thought enough of him to draft him in the 6th round for $300K less than two months ago a few teams will at least consider giving him a second chance. But maybe he doesn't want one.
Sure, you might think a clubhouse would find this a lot less forgiveable than domestic abuse, PED usage or just being a racist or a jerk, but I bet it's not actually that cut and dried. Maybe the team was complete mess, or they all hated the manager, or their living conditions were especially awful. Some of the other players probably felt the same way he did or at least think it was funny, even a huge line was crossed.