The roster bonus was, I think, a couple hundred thou - chump change, really - like throwing a deck chair off the Queen Mary when compared to the $$$multi-million$$$ signing bonus that the Bills still have to pay Dockery regardless of whether he plays for us or not ($18 million signing bonus, the third largest in NFL history at his position).
So it definitely wasn't about a few hundred thousand dollars roster bonus - it just became apparent that he couldn't keep up in the no-huddle, his overall play seemed to be slipping, and his attitude was worsening. Much like FatBoy Peters, once Dockery got the big bucks - the $18 million - he just didn't seem to give a !@#$ about excelling at football any more.
If you don't think so, then why has no one else signed the guy?