Because he realized he's not even good enough for the CFL.
I think you are right...
When I first saw these articles, I looked up about ten different sources..
Several of them noted from anonymous sources his performance was improving but was still lacking the drive to only make the cut to third on the depth chart...
I think he believed all the hype about him and thought he would have a walk in the park in the CFl and sat on his ass and expected a position...
My guess this is the end of his career...