Gardner, the last player on the team from its 2009 World Series title, hit .201 with five homers and 18 RBIs in the first half, then hit .239 with five homers and 21 RBIs in the second half.
The 38-year-old outfielder agreed early in spring training to a $5.15 million, one-year contract that included a $2.3 million player option and a $7.15 million club option with a $1.15 million buyout.
Gardner, an All-Star in 2015. has a .256 batting average with 139 homers and 587 RBIs in 14 big league seasons.
O’Day, a side-arming right-hander who turned 39 on Oct. 22, had a 3.38 ERA in 12 appearances. He was sidelined between April 29 and June 30 with a strained rotator cuff in his pitching shoulder, returned for two outings, then didn’t pitch after July 4 due to a strained left hamstring.
O’Day agreed last February to a $3.15 million, one-year contract that included a $1.4 million player option and a $3.15 million club option with a $700,000 buyout. He is a veteran of 14 major league seasons.