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Andy Pettitte has already been in Joe Girardi's ear, telling the Yankees manager at every turn that he feels fine and could be back soon, despite a left groin strain that the team expects to keep him out until mid-August.

The 38-year-old left-hander played catch for about 5 minutes from 60 feet before New York played the Kansas City Royals on Saturday. He'll fly to Florida on Monday for more rehab.

"I mean, I feel good," Pettitte said. "I'm not having any problems at all."

Pettitte hurt the groin while throwing a pitch last weekend against Tampa Bay. An MRI showed a Grade 1 strain, which is the mildest on a scale of 1 to 3, and Pettitte was put on the disabled list retroactive to Monday. It's his eighth trip to the DL, but first since 2008.

He was also sidelined by a groin strain in 2001.

"They told me to take it day-by-day," Pettitte said. "As soon as I can start long tossing, that'll be great, because I can keep my arm strength up."

Sergio Mitre came off the disabled list Saturday to start against the Royals in Pettitte's place. He's been out since June 15 with a strained muscle in his left side.

Pettitte was asked whether the timeline of mid-to-late August for his return was realistic, and the veteran All-Star said no — in a positive way. He hopes to be back much sooner.

"It doesn't seem realistic to me at all, but I haven't gotten on the mound," Pettitte said. "When I get on the mound, I'll be able to say, and hopefully I won't have any setbacks."

Pettitte is in the middle of one of the best seasons of his 16-year career. He's 11-2 in 18 starts and if the season was over, his 2.88 ERA would match 1997 for his best ERA as an American League pitcher. He had a 2.39 ERA for Houston in 2005.

Girardi said that Pettitte kept telling him in the dugout Friday night that he felt fine, but the manager said he wants to take a cautious approach. The Yankees have been surging lately and led the division by four games entering Saturday, and Girardi said he wants to make sure that Pettitte has no problems during the stretch run and the playoffs.

"It's one thing to walk around, it's another thing to get off the mound and push," Girardi said. "I'm very happy with the progress he's making and that he feels good. I'll feel a lot better when he starts throwing off the mound and says he doesn't feel anything, because that's where you're going to exert yourself in that area.

"Whatever it takes, when he comes back, I don't want this to be a recurring problem."

The Yankees optioned reliever Jonathan Albaladejo to make room for Mitre, who pitched six innings in a rehab outing for Triple-A Scranton/Wilkes-Barre on Monday. He's making his first start since May 16 after spending time working out of the bullpen before his injury.

In other news, Brett Gardner made a quick trip to the hospital on Saturday morning because of an acid reflux problem that he's had for years. Girardi expected the speedy outfielder back at the ballpark by the start of the game and to have him available off the bench.

"He'll be fine," said Girardi, who thinks the hospital trip was caused by something that Gardner ate on Friday. "This is something he's had for 14, 15 years. It happens from time to time, he says, and he should be fine."

Fellow outfielder Nick Swisher was also held out of the starting lineup after being a late scratch Friday night with a left Achilles' injury. Swisher had his ankle bandaged before the game, but took batting practice and said he hopes to start the series finale Sunday.

Swisher still didn't know what caused the injury, but said it was feeling much better.

"I got some treatment yesterday and whatever it was, I feel way better today," Swisher said. "Right now everything is clicking, man. You want to be in there."