The Oakland Athletics placed outfielder Josh Reddick on the 15-day disabled list with a hyperextended left knee and activated reliever Ryan Cook from the DL on Tuesday.

Reddick hurt the knee during Saturday's 11-3 win over the Angels. Craig Gentry is expected to receive most of the playing time in the outfield in Reddick's place.

The 27-year-old Reddick is batting .214 with four homers and 22 RBIs in 50 games this season. His most productive year came in 2012 when he hit 32 home runs and had 85 RBIs while batting .242.

Reddick is a career .239 hitter with 54 homers and 178 RBIs for the Boston Red Sox and the A's.

Cook was out for a month with a strained forearm. The 26-year-old has pitched in 12 games this season and is 0-1 with a 2.92 ERA in 12 1/3 innings. While pitching in 71 games each of the previous two seasons, Cook compiled a 12-6 record with 16 saves, including 14 in 2012, and 44 holds.