Daisuke Matsuzaka headed to DL

BOSTON -- Boston Red Sox pitcher Daisuke Matsuzaka is going to be placed on the 15-day disabled list Wednesday because of a sprain in his right elbow, manager Terry Francona said after Tuesday night's game against the Baltimore Orioles was postponed because of rain.

The right-hander had an MRI done Tuesday afternoon, and the images showed the sprain, Francona said. A more detailed statement from medical director Thomas Gill is expected Wednesday, according to the Sox.

Michael Bowden, who had joined the Red Sox on Tuesday from Triple-A Pawtucket and was in the clubhouse, will be officially called up Wednesday to take Matsuzaka's spot on the roster.

So over the last two days Boston has lost two-fifths of its starting rotation. On Monday, John Lackey (2-5, 8.01) was placed on the DL, also because of right elbow woes.

The Red Sox are looking into their bullpen to replace Lackey and Matsuzaka for now. Tim Wakefield, who was going to start Tuesday night in Lackey's spot, instead will pitch Sunday night's game against the Chicago Cubs at Fenway Park. Alfredo Aceves, who worked three innings of relief in Matsuzaka's start Monday night, will start against the Cubs on Saturday night.

There is no makeup date for Tuesday's rainout.

The Sox were concerned about Matsuzaka after watching him struggle Monday night against the Orioles. Matsuzaka was raked for five runs on five hits and seven walks in only 4 1/3 innings. While the results were bad, it was how Matsuzaka looked on the mound that worried the Sox even more. He wasn't finishing his pitches, either because of pain or because he was afraid he would experience pain if he extended his arm 100 percent, Francona said.

Francona said he didn't know of a particular pitch that caused the injury, but it's likely some of Matsuzaka's issues began flaring up on April 29, when he had to leave a start against the Seattle Mariners after only four-plus innings because of tightness in the elbow.

"We'll shut him down for a period of whatever time we need," Francona said. "The doctors don't know for how long."

As to how the injury happened, Francona said, "We really don't know. I don't think Daisuke knows.

"We're going to get Lackey healthy, we're going to get Daisuke healthy. Until we do we'll try to win with someone else."

Matsuzaka (3-3, 5.30) was asked to meet with the media Tuesday night, but he sent word through the PR staff that he would talk about his injury Wednesday.

Wakefield and Aceves, meanwhile, are those "someone elses" for Francona and the Sox for the time being.

Wakefield, of course, has a long history as a starter. He ranks first in Red Sox history in starts (409), the most starts for one team by any active pitcher in the majors. Primarily a long man out of the bullpen this season, Wakefield has made two spot starts. He went 5 1/3 innings on May 1, allowing one run on three hits to the Mariners. On May 6, Wakefield was tagged for eight runs (six earned) in 4 1/3 innings in a 9-2 loss to the Minnesota Twins.

At the age of 44 years and 288 days, making him the oldest active player in the big leagues and oldest Red Sox player ever, Wakefield does not lack for experience.

"He has been doing this since I was a kid," Francona joked.

Francona said that because Wakefield is being skipped in the rotation because of the rainout, it's possible he could get an inning or so out of the bullpen over the next few days or throw a side session to get in some work.

Aceves was signed as a free agent to give the Sox some versatility. He was mostly a reliever in parts of three seasons for the New York Yankees, appearing in 59 games, five of them starts. But he was a starter for most of his six years in the Mexican League and in the minors for the Yankees, and that experience was one reason Boston signed him.

"We think he can go out there and do a good job," Francona said.

In the meantime, Francona has his top three starters lined up for the next three games. Clay Buchholz will start Wednesday night's game against the Detroit Tigers, with Josh Beckett following in the series finale against the Tigers on Thursday. Jon Lester will open the series against the Cubs Friday night.

As for Bowden, his stay in Boston may be brief. He gives the Red Sox an extra bullpen arm for the next two days, but it's possible he could be headed back to Pawtucket on Friday, when reliever Dan Wheeler (calf) is eligible to come off the DL.

Steven Krasner is a frequent contributor to ESPNBoston.com.