Piscotty was batting eighth and starting in right field for Tuesday night's game at Boston, which was delayed by rain. Piscotty had been away from the team following the death of his mother. Gretchen Piscotty died May 6 from amyotrophic lateral sclerosis, also known as Lou Gehrig's Disease.
Piscotty is hitting .248 with two home runs and 13 RBIs in 34 games.
To make room for Piscotty and with Trevor Cahill (elbow) expected to return from the disabled list on Wednesday, the A's also optioned right-hander Kendall Graveman to Triple-A Nashville.
Graveman, called up last Friday, earned his first win of the year in a solid start against the Yankees and was scheduled to start Wednesday against the Red Sox. He's 1-5 with a 7.60 ERA over seven starts with the A's this season.