Reddick, who leads the Athletics with 29 home runs and 79 RBIs, is 0 for 27 in his last six games. His batting average has slipped to .242.
A's center fielder Coco Crisp is out of the lineup for the seventh game in a row because of an eye infection. Crisp last started on Sept. 18 against Detroit before he was removed from that game in the fourth inning.
Oakland entered Tuesday trailing first-place Texas by five games in the AL West.