The Red Sox are hoping that Josh Beckett’s oblique strain is of the mild variety.

Journal / Gretchen Ertl

BOSTON — With no additional information to share on Josh Beckett’s strained right oblique muscle, the Red Sox still have their ace slotted to start Game Three of Boston’s American League Division Series against the Los Angeles Angels, Sunday at Fenway Park.

The 28-year-old right-hander is expected to play catch today, and then throw a side session on Thursday, at which point the club will know a lot more about where Beckett stands, said Sox manager Terry Francona.

Following Boston’s regular-season finale against the New York Yankees on Sunday night, Francona confirmed that Beckett would not be pitching in Game One after straining the oblique muscle while throwing a side session last Friday. It was at the end of the session, thrown in the rain at Fenway, after tossing his 40th pitch that Beckett indicated he had tweaked the muscle, Francona said.

When asked yesterday if the team had a clearer picture of the severity of Beckett’s injury, Francona said that nothing had changed since his comments late Sunday. But he later added that Beckett does feel better.

“To be honest with you, and I’m not making light of it, I don’t know that you ever fully know a grade of something until it’s over, unless there’s some bleeding, which there isn’t,” Francona said. “I don’t think it’s so much the grade as how quickly it goes away so he can pitch effectively. That’s more important.”

Beckett made a brief stop at his locker during the 45 minutes that the Red Sox clubhouse was open to the media yesterday afternoon, but declined a request for an interview.

An injury to the oblique muscles — the band of abdominal muscles that wrap around a person’s side at an angle, attaching at the ribs and the pelvis — typically takes a long time, even several weeks, to heal. Mike Lowell can attest to that. The Sox third baseman was on the disabled list from Aug. 13 to Sept. 5 also with a strained right oblique muscle.

“I think it depends on how severe the strain was,” said Lowell, whose right hip flexor is what continues to give him problems now. “I think they label it as four different grades, and I don’t know what Josh had. I’m hoping it’s the least one. But I think it’s almost a comfort level with yourself on when you think you can do something.

“I remember when I swung for the first time,“ he added. “Since we were at a point in the season when they could take their time, they took their time. In the postseason, I think maybe I would have been pushed up a couple days and I don’t think it would have made a difference. So I think it depends on where you’re at, first of all,and how long it takes for you to feel comfortable to be able in my case swing and Josh’s case throw.”

The shuffling of the rotation — with Jon Lester starting Game 1 and Daisuke Matsuzaka starting Game Two so that Beckett doesn’t have to pitch until Sunday — doesn’t appear to have the Red Sox particularly concerned.

“I think you always want Josh throwing as many games as you can in the postseason because his track record is unbelievable,” Lowell said. “But Dice arguably pitched the most important game for us, which was Game Seven last year in the ALCS, and he did well. So we have guys with experience and have pitched well in big games, so you’ve got to feel good about that.”

And, as Francona points out, injuries not only aren’t exactly something new to this ball club, they also haven’t stood in the way of the Red Sox’ enjoying a good amount of success during the regular season.

“We have to answer the questions [about the various players’ injuries], and probably the hardest thing is if you don’t know. That’s where you can get into a little bit of a bind,” he said. “But we’ve communicated pretty well with everybody, and I think everybody’s on the same page.

“Trying to answer it today because we have a media event doesn’t make sense. That’s why there’s a workout and we’ve planned everything, and we’ll try to do things at the appropriate time so we can make the best possible decisions. . . . . But we’ve been able to win 95 games with not everybody healthy. So we’ll continue to compete regardless of what happens.”

cthorn@projo.com