I highly doubt it was due to his performance as a racer. He has been pretty much in the top 10 at every major race since PNB last year. It doesn't say anything about a breech of contract, so I would think he wasn't meshing well with others on the team and/or management....but that's just an assumption. Guess we will need to hear the whole story.
Great driver and good guy. Wish him luck. I don't think it will be too long before someone else picks him up.