Gardner, who went on the disabled list on April 18 with a right elbow strain that eventually required surgery to remove a bone spur, was activated before Tuesday night's game with the Minnesota Twins at Target Field. Gardner, however, did not play in the Yankees' 5-4 loss.
"We feel that Gardy can help us on the basepaths," manager Joe Girardi said before the game. "I don't know how realistic it is that he could do more."
The Yankees also activated right-hander David Aardsma from the disabled list Tuesday. Utility player Steve Pearce and LHP Justin Thomas were designated for assignment to make room for Gardner and Aardsma.
Gardner, who suffered two setbacks in his rehabilitation while swinging at live pitching, has yet to take batting practice and for now, Girardi plans to use him strictly as a pinch runner and late-inning defensive replacement.
"Forget trying to play every day or anything like that," Gardner said. "Any kind of role they want to use me in late in the game, pinch run, play defense or maybe get a guy over, I'd be ready for."
Gardner suffered the injury diving for a ball in left field and although the injury was to his non-throwing arm, it caused him pain while swinging a bat. In the past week, he has hit off a tee and done some work in the indoor batting cage, but will not hit against live pitching on the field until the Yankees get to Toronto on Thursday for a four-game weekend series against the Blue Jays.
"He's not ready to hit in a game," Girardi said. "So the best we can do right now is use him as a pinch runner and a defender."
As their starting left fielder, Gardner led the Yankees in stolen bases with 47 in 2010 and 49 in 2011, and shared the league lead with Coco Crisp last year. He was replaced in the outfield by a platoon of 40-year-old Raul Ibanez and 35-year-old Andruw Jones, who have provided power -- a combined 31 home runs and 91 RBIs -- but not Gardner's defense or ability to get on base and create runs, a season-long weakness for the Yankees.
In Gardner's absence, the Yankees have lacked for speed on the basepaths -- currently 37-year-old Alex Rodriguez leads the team with 13 steals, and 38-year-old Ichiro Suzuki is second, with 12 as a Yankee -- and this weekend, a baserunning gaffe by rookie Melky Mesa nearly cost them an important game against Oakland.
"I think it can help because we've been in a lot of close games the last 10 days, two weeks," Girardi said.
But it seems unlikely the Yankees would carry Gardner on their postseason roster if he was unable to hit.
"I haven't even thought about that, to be honest with you,'' Gardner said. "A lot of things can happen between now and then and I'll just focus on trying to stay healthy. I'm just excited to be here and able to play again.''
Aardsma has not pitched since 2010 with Seattle. He had Tommy John surgery last year. Girardi says he will be cautious with how he uses Aardsma out of the bullpen with the Yankees in a tight division race.
Information from The Associated Press was used in this report.