Reddick is out of Tuesday's lineup against Cleveland and Oakland manager Bob Melvin says he will likely be unavailable for the remainder of the four-game series, which concludes Thursday.
Reddick has struggled this season, batting. 152, the third-lowest average in the American League. He's also in a 3-for-27 slump in his last 10 games.
Reddick was a key member of Oakland's drive to the AL West title last season when he batted .242 with 32 homers and 85 RBIs. He has one homer and 14 RBIs in 29 games this season. Michael Taylor is starting in right field against Cleveland.