Manager Lou Piniella will not get any help from Mark Prior this season.
The injury-plagued righthander underwent shoulder surgery on Tuesday and will miss the rest of the season, the Cubs announced on Wednesday.
Dr. James Andrews performed a debridement of Prior's right rotator cuff and repaired labral and capsular injuries in the shoulder.
Prior will begin a comprehensive rehabilitation program in Birmingham overseen by Andrews and the Cubs medical staff.
Prior Out For Season After Shoulder Surgery