The move, retroactive to Friday, came after the rookie slugger was scratched from the starting lineup for a second straight game.
Casas is batting .263 with 24 home runs and 65 RBIs in 132 games.
Casas ranks first among American League rookies in walks (70) and OPS (.857) and is second in home runs. He has hit .317 with 15 home runs in 54 games since the All-Star break.
The Red Sox recalled infielder Bobby Dalbec from Triple-A Worcester. Dalbec hit 25 home runs as a rookie in 2021, the sixth-highest rookie total in Red Sox history.