The team made the announcement Thursday and also placed Mendick on the 10-day injured list.
Mendick, who is hitting .289 with three home runs, 15 RBIs and a .786 OPS in 31 games this season, underwent an MRI after leaving Wednesday's game following a collision with left fielder Adam Haseley on a foul pop in the second inning.
Meanwhile, right fielder Adam Engel, who left Wednesday's game after three innings, was placed on the 10-day injured list because of a strained hamstring.
In other moves, infielder/outfielder Gavin Sheets was recalled from Triple-A Charlotte, infielder Lenyn Sosa was called up from Double-A Birmingham and outfielder Eloy Jimenez was transferred to the 60-day injured list.
Sosa, 22, is hitting .331 with 14 home runs, 48 RBIs and a .933 OPS in 62 games for Birmingham this season.