According to the May 8 St. Louis Post-Dispatch, "The Cardinals hesitate to call it another setback in the ongoing saga of Mark Mulder's two-year recovery from a shoulder injury, but Wednesday's decision to sideline the lefty for a week or more is at least a sidetrack. After meeting with the team doctor Wednesday, Mulder was judged to have a mild rotator cuff strain and was removed from his rehab assignment. He will be given at least seven days, possibly as much as two weeks, to rest his surgically rebuilt joint before again attempting a rehab assignment that would bring him back healthy to the majors."
This guy should just hang 'em up. I doubt he'll ever be healthy enough to pitch again.
STLtoday - Mulder is back on the sidelines