Joba Chamberlain firmly believes he will pitch for the Yankees this season. When, though, is something the right-handed reliever can't deliver an accurate answer about. "I can promise you I am going to pitch, I can promise you that,'' Chamberlain said in the Yankees' Tropicana Field clubhouse yesterday afternoon. "Tell everybody it's going to happen.'' Chamberlain is coming back from last summer's Tommy John surgery on his right elbow and a dislocated right ankle suffered during a trampoline accident during spring training.