Mastrobuoni was called up from Triple-A Iowa on Tuesday.
Mastrobuoni will return to the major-league roster after being sent down May 20, replacing Mike Tauchman (groin) with the Cubs after Tauchman was placed on the 10-day injured list Tuesday. Mastrobuoni produced a .264 average with three home runs, 14 RBI, 16 runs scored and four stolen bases over 87 at-bats in 22 games with Iowa since his demotion.