BOSTON — After last night’s doubleheader against the Yankees, Red Sox manager Terry Francona announced that pitcher Josh Beckett will not start for Boston in Game One of the American League Division Series against the Los Angeles Angels on Wednesday.

The right-hander suffered a strained oblique muscle while throwing a side session at Fenway Friday afternoon in the rain.

Jon Lester will instead pitch the opener for Boston. Diasuke Matsuzaka will throw Game Two on Friday, also in Anaheim.

Beckett is slotted to pitch Sunday when the series comes to Boston.

“If it goes the wrong way, we’re going to use very good judgment,” Francona said. “Friday was actually discussed and I think after [Sox general manager] Theo (Epstein) and I and [pitching coach] John Farrell talked about it more and more and more, we thought [Wednesday] was pushing it. Because when you’re messing around with maybe cutting short a side session or not having enough throwing, it’s not just health; it’s competing. He has to be able to go out there and execute his pitches. But I think he’s going to be OK.”

Plenty in reserve

Francona reiterated yesterday that third baseman Mike Lowell (right-hip flexor) will participate in the club’s workout tomorrow in Anaheim before a decision is made whether he will play against the Angels.

The acquisition of Mark Kotsay from Atlanta late last month when J.D. Drew was placed on the DL looks more and more to have been a wise move given the cloud of uncertainty that continues to hang over both Drew and Lowell.

Kotsay, who can play center and right field, along with first base, played first in yesterday’s first game, hitting a double in Boston’s two-run eighth.

“He gives us a very experienced bat,” Francona said. “He’s a very good right fielder, and a very underrated first baseman. He has real good actions and good footwork. He just hasn’t been out there very much. He brings a very good veteran presence. He competes. He likes to play and that’s why he came here. We’re very fortunate we got him. He’s been an important addition.”

Dice-K solid

Although he took the loss in Game One, Daisuke Matsuzaka’s final regular-season outing, especially given the less-than-ideal pre-game conditions, was solid, Francona said. Suffering his first loss since a 7-5 setback to Los Angeles on July 28, he gave up three runs — all of which came on Xavier Nady’s two-out three-run homer in the fourth after Matsuzaka had issued back-to-back walks to Bobby Abreu and Alex Rodriguez — in a four-inning stint.

“It was getting the ball down around the corner that cost us three, but I thought he threw the ball really well,” Francona said. “We didn’t want to get him much farther than that just because of what we have in front of us and the way he warmed up because of the weather.”

Finishing the regular season at 18-3 with a 2.90 ERA, Matsuzaka’s five strikeouts brings his two-season total with Boston to 355, the most ever in Sox history and the most by an American League pitcher since Bert Blyleven struck out 359 between the 1970 and ’71 seasons with Minnesota.

Beat goes on

Jacoby Ellsbury extended his career-best hitting streak to 18 games with his RBI single in the eighth inning of Game One. It is the longest hitting streak by a Major League rookie this season and the longest by a Red Sox rookie since Nomar Garciaparra’s 30-game streak in 1997.

cthorn@projo.com