Mark Prior started the season on the disabled list, and he may end it there. The right-hander will not accompany the team on its trip to Denver but would go back to Chicago to have his shoulder examined by team physician Stephen Gryzlo. The Cubs' brass became concerned after Prior was knocked around in an 8-6 loss to the Milwaukee Brewers on Thursday. Pitching coach Larry Rothschild said a dip in velocity in the third inning couldn't be explained and prompted the exam.