Stauffer was scheduled to start Thursday's game for Tucson. But earlier this week, Stauffer started to experience soreness in his right shoulder. He has since returned to San Diego to be examined.
Stauffer allowed two runs on four hits in three innings of his first and only outing with Triple-A Tucson on Aug. 11.
Stauffer was in line to start Opening Day until the final week of Spring Training when he first started to feel discomfort in his elbow. He started the season on the disabled list, but he was activated on May 14 in time for a start in Washington.
Stauffer experienced soreness in his elbow -- in his flexor tendon bundle -- late in that outing against the Nationals. He allowed four runs (three earned) in five innings in that game and eventually landed on the disabled list again on May 18, retroactive to May 15.