I bump him to AAA to start the year, and tell him he's the first guy up, and they'll make room for him if he produces down there. This seems like a confidence issue (as others have stated), and I think a month in Rochester would do wonders for that. Tell him to go after hitters, take risks and try and groove his fastball.
Burnett has all the tools, and I think he is evidence that the Twins way of slowly bringing up their prospects has merit. Realistically had he not been rushed, he would have been looking at a full season of AAA in 2010, and half a season in 2011.