The Cubs optioned Alcantara to Triple-A Iowa on Tuesday, Vinnie Duber of the Chicago Sun-Times reports.
The 23-year-old outfielder will lose his place on the active roster to make room for Matt Shaw's return from the injured list. Alcantara owns a .906 OPS across 180 plate appearances in the minors, but he's gone just 1-for-9 with a walk and four strikeouts in 12 games at the major-league level this year.