The NFLPA is a terrible organization. They are simply going to try to help him recover as much money as possible but not being able to see his contract the "conduct unbecoming" clause could reach far and we will not know unless this gets ugly. The club may play ball just to get rid of him which is the ultimate goal for them now. This act is a felony and I don't think he can plea it low enough to get to a misdeamenor. So the club may have a leg to stand on.
I love how Pierce was quoted as saying he is willing to testify to the grand jury. How nice of him seeing if he didn't he prob would be arrested.