Tabata hit .289 in 27 games with Pittsburgh this season after beginning the year in Triple-A Indianapolis. Tabata, who signed a six-year extension with the Pirates in 2011, has struggled to stay in the big leagues over the past two years. He spoiled Scherzer's chance at a perfect game with two outs in the ninth inning on June 20 when he was hit by a pitch.
The Pirates also designated right-handed pitcher Chris Volstad for assignment and called up infielder Steve Lombardozzi and outfielder Gorkys Hernandez from Triple-A. Hernandez started in right field on Sunday against Atlanta.