He didn't fit what the new regime in town wanted for their Offense. I think it's as simple as that. They are going to have 7 picks in the first four rounds next year. That will allow them to build the kind of team they want from the ground up.
It does suck for this years team. However, it's also a shot at everyone who is underperforming at this point. I'm just glad I'm not a Browns fan that just invested in a Trent Richardson jersey because he was supposed to be the face of the franchise.