Cubs starting pitcher Andrew Cashner could be sidelined until after the All-Star break after aggravating his strained rotator cuff. Cashner was originally placed on the disabled list with the injury six weeks ago. An MRI exam revealed the same inflammation in the same spot as Cashner's first MRI exam showed in early April. Until feeling pain Monday while warming up for a scheduled extended-spring start, Cashner hadn't had a setback and was expected to start a minor-league rehab assignment sometime this weekend. "I feel real bad for him," general manager Jim Hendry said. "He's worked real hard. His rehab's gone really well up to this point. Obviously, the main goal will be just to continue to get it right so [he can] continue to have a bright future."