Last season, Mesoraco had surgery to repair the labrum in his left shoulder. The shoulder continued to plague Mesoraco in spring training this season, and he spent 20 games -- the maximum time allowed -- on a rehab assignment in the minors.
Manager Bryan Price told reporters in Denver that the shoulder strain Mesoraco is dealing with is not related to last year's injury. Price said no structural damage was found during an MRI, but he didn't put a timetable on Mesoraco's potential return.
Right-hander Ariel Hernandez has been recalled from Triple-A Louisville to take Mesoraco's roster spot.