The 32-year-old Abreu suffered the injury while taking batting practice at Legends Field, manager Joe Torre said. Abreu felt a twinge after one swing and then continued to bat, which aggravated the injury.
"It's just one of those things," Torre said. "I guess the good news is that it's early and you can afford a couple of weeks right now."
Abreu left the Yankees' Spring Training complex without speaking to reporters. Injuries of this nature tend to be variable among players, but the consensus appears that Abreu may not be ready to bat in a Spring Training game until the exhibition schedule is half-complete.
"He had a significant oblique strain, and it could be timely," general manager Brian Cashman said. "I know Joe said two weeks, and I'll probably say three weeks. But we'll see. It could be one week."
Torre said that Opening Day is not considered to be in jeopardy for Abreu, who batted .330 with seven home runs and 42 RBIs in 58 games for New York last season after being acquired from the Phillies on July 30.
"You're happy that it happened at this juncture because you do have time," Torre said. "The only thing he's going to have to do is basically keep his sanity and keep in shape. He's going to be limited on what he can do, conditioning-wise."
Cashman was less optimistic, saying that he could envision a situation in which Abreu was not ready for the Yankees' April 2 opener against Tampa Bay. That would be a "worst-case scenario," however, with Abreu returning to action too late to round into regular-season form.
"If it was going to happen, you'd rather it happen on Feb. 26 than June 26, or March 26," Cashman said. "Right now, I know where he's going to be spending his days."
Abreu is expected back to the team's complex on Tuesday, but will be limited over the next few weeks to simple cardiovascular exercises, such as riding a stationary bicycle. He will be unable to throw or swing a bat, which will put his readiness behind the Yankees' active outfielders.
"The only bad part about this is that you basically shut down," Torre said.
Kevin Thompson and Kevin Reese will also be among those picking up innings while Abreu heals. The Yankees open their exhibition schedule on Thursday against the Twins.
Even with an outfielder down, both Cashman and Torre said nothing has changed regarding the organization's stance on Williams, 38, who has not accepted a long-standing non-roster invitation to Spring Training.
Torre has not spoken recently to Williams, who did not return a pair of telephone messages from the manager. Williams continues to work out near his Armonk, N.Y., home, but by not reporting to Tampa, he appears to have ended his chances at playing a 17th season in Yankees pinstripes.
"That's not an option we're looking at," Cashman said. "Bobby is coming back. The question is when."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.