Reyes underwent an MRI on his sore right shoulder Tuesday, John Denton of MLB.com reports.
Reyes finally had a healthy season last year and wound up with 29 saves and a 3.24 ERA, but it looks as though he may not be so lucky this season. For now, he and the Cardinals are treating his issue as merely lingering soreness from last season, but the results of the MRI could potentially reveal a more serious injury.