It is a sponsor deal, a certain sponsor wants him there, sponsors are hard to come by these days, so you do what you can to make them happy. Tri City is one of a number of great race tracks in the STL area. Go over and watch him race there, you will enjoy yourself there as well. The 50 car is getting some modifications right now and should be back strong next weekend.
He plans on being there as of now, car is still at Rayburn's right now. Major changes being made, hopefully the car will respond better when he gets it back.