De La Rosa had been pitching at Triple-A Salt Lake but came back to Anaheim on Wednesday to be examined. He received a cortisone injection in his AC joint and won't throw again for two days before heading back to continue rehab.
"It killed a lot of the inflammation," De La Rosa said, adding he had "no concern whatsoever. I just needed to get this taken care of."
He said he was pleased with his consistent velocity -- 92-93 mph, with some 94-95s thrown in -- before the tightness happened.
Scioscia said De La Rosa was showing the velocity needed to pitch in Major Leagues before the setback. De La Rosa experienced forearm tightness in the spring that cost him most of the Cactus League season. He rehabbed and came back to pitch in one game for the Angels but with diminished velocity, so he went back on the disabled list.