NEW YORK -- Yankees right-hander Michael Pineda had successful surgery on his right shoulder on Tuesday, manager Joe Girardi said before New York's game against the Orioles.

The right-hander underwent an arthroscopic procedure in New York to repair a tear in the labrum of his right shoulder and is expected to be out about a year.

"I heard it went well," Girardi said. "It was done today by Dr. [David] Altchek and Dr. [Christopher] Ahmad. The rehab doesn't start right now, but it starts now, basically. We're anxious to get this guy back, and now he's on the road to recovery."

Altchek, the Mets' team physician and one of the nation's leading arm specialists, was expected to perform the procedure alongside Ahmad, the Yankees' team physician.

Pineda, who came over from the Mariners this past offseason in a high-profile deal for top prospect Jesus Montero and right-handed pitcher Hector Noesi, began experiencing weakness in his right shoulder during an extended spring game, weeks after he felt discomfort during a regular Spring Training start.

Pineda was 9-10 with a 3.74 ERA in 171 innings last year as a rookie with the Mariners.

Yanks play it safe with Swisher, Gardner

NEW YORK -- Joe Girardi cautioned against following timetables for the progress and rehabilitation of outfielders Nick Swisher and Brett Gardner, but the Yankees' manager hopes to have the two back in the lineup by early next week, at the latest.

Gardner has been on the 15-day disabled list with a right elbow injury he sustained in an April 17 game against the Twins. Swisher has been sidelined with a left hamstring injury since he tweaked it on Sunday against the Tigers.

Gardner is eligible to come off the disabled list on Thursday, but because Girardi wants the left fielder to play in a rehab game or two, the skipper said it seems more unlikely that Gardner will be back in the lineup for Thursday's series opener in Kansas City.

"He's supposed to do more stuff today," Girardi said on Tuesday. "We're going to see where he's at after today. We're starting to get to the point where Thursday might be a little doubtful, just because he's going to have to go play a game or two."

The Yankees have been using reserve outfielders Andruw Jones and Raul Ibanez with the two starters out, and Eduardo Nunez earned his second start in left field in as many days on Tuesday.

As for Swisher, Girardi said the Yankees are also going with a conservative timetable to wait and see how his body responds to running the bases and other baseball activity.

"If you don't do anything for two or three days, and then you go out and run the bases, it's kind of hard to declare him ready," Girardi said. "One of the reasons that we give somewhat of a conservative timetable sometimes on guys is, if all of a sudden you say he's going to be ready in three days or four days and they're not ready, then red flags go up everywhere. ... I believe we'll have him back Tuesday. If we get him back sooner, would I be happy? Absolutely."

Pettitte may return after one more start

NEW YORK -- As Andy Pettitte began his testimony for the prosecution in the federal perjury trial of Roger Clemens in Washington, D.C., on Tuesday, Yankees manager Joe Girardi was back in New York talking about the left-hander's prospects of soon joining the club.

Pettitte, trying to make a comeback after not pitching in 2011, threw 96 pitches in an extended spring game on Monday at the Phillies' complex in Clearwater, Fla.

After allowing six runs (five earned) over six abbreviated innings, Pettitte said that he feels ready to return to the Majors, but Girardi said the lefty is expected to get another start before joining the Yankees.

Girardi said he did not know where that start would be, or if Pettitte would receive an extra day's rest beforehand, but the manager said it could very well be the last step.

"It could be; it may not be," Girardi said. "That has to be determined by the people that are watching him. I get reports, but my eyes aren't on him to exactly know what's going on."

Girardi spoke to Pettitte only briefly and knew the pitcher had his obligations to fulfill in Washington.

"I spoke to him before he pitched; he didn't really lead me to believe it was going to affect the way he was going to throw the baseball," Girardi said of Pettitte's impending testimony. "But I'm sure it was on his mind. I don't know how it wouldn't be."

Bombers bits

• The Red Sox and Yankees announced on Tuesday that their rained out April 22 game in Boston will be made up as the opener of a day-night doubleheader on July 7 at Fenway Park. The first game of the twin bill will be at 12:35 p.m. ET, with the originally scheduled nightcap to follow at 7:15 p.m. Fans holding tickets to the April 22 rainout may use those tickets for the 12:35 p.m. game.

• On May Day, Girardi took the opportunity to reflect on his team's April performance.

"I think it's a month where you can look at it half-empty or half-full," Girardi said. "With the struggles that our starting pitching has had, are we lucky to be 13-9? Probably. ... I'm pleased with where we are. I think we're swinging the bats pretty good, but there are still some guys that we need to get on track. We're 13-9, we've had struggles in the rotation, our long man is going to step in on Thursday, we haven't gotten a ton of production from Robbie Cano and we're still 13-9. So I think it tells you the depth of our club."

• With injuries to Swisher and Gardner, the Yankees are looking beyond Jones and Ibanez, handing Nunez -- who has been used primarily as a backup infielder -- his second consecutive start in left field on Tuesday.

"He enjoyed it," Girardi said of Nunez's outfield debut on Monday. "We enjoyed watching it. And he's going to get some time [in left]."