Alcala was placed on the 15-day injured list Tuesday with a right forearm extensor muscle strain, Betsy Helfand of the St. Paul Pioneer Press reports.
The 27-year-old reliever holds a 6.46 ERA and 1.37 WHIP through 15.1 innings and will now be forced out of action for at least two weeks. Alcala will be replaced on the active roster by Jose De Leon, who was selected from Triple-A St. Paul on Tuesday.