Daisuke Matsuzaka likely out month-plus

BOSTON -- The Red Sox expect Daisuke Matsuzaka to be out for a minimum of a month after he was diagnosed with a sprained ulnar collateral ligament and strained flexor, an injury that when severe enough often results in Tommy John tendon transfer surgery.

The Red Sox are hoping that Matsuzaka will be able to avoid the surgery, which would sideline him for the rest of the season, and that he will respond to rehabilitation, according to a club source. A statement from team medical director Thomas Gill said that Matsuzaka will be re-examined in two weeks.

But the Sox have not ruled out the procedure, because they have yet to determine the severity of the injury, according to a club source, who added that won't be known until further evaluation takes place.

Manager Terry Francona said Matsuzaka, who was officially placed on the 15-day disabled list Wednesday, will not throw at all in the interim and said that it is "probably ambitious that he will throw (in two weeks). That's just the first time he will be looked at. I don't think we should expect him to be ready to throw then."

The ulnar collateral ligament is one of the tissues that connects the humerus bone in the upper arm to the two bones of the forearm. It acts as a stabilizer in the elbow, allowing it to withstand the stresses created by throwing a baseball. When the UCL weakens and stretches, that is technically called a sprain, and prevents a pitcher from throwing with full velocity and typical control. A more complete tear requires the building of a new ligament, which Tommy John surgery accomplishes by transferring a tendon, often from the forearm.

"Normally, the time down -- two weeks down, three weeks down, four weeks down -- that's normally about what it takes to get back to the mound,'' Francona said. "So, you can kind of do the math: If a guy is down three or four weeks, and it takes three or four weeks to get back on the mound, they're not going to be back on a big league mound real quick."

Matsuzaka, meeting with reporters Wednesday afternoon, said he first experienced discomfort on April 29 in a start against the Seattle Mariners, a game in which he was pulled in the fifth inning because of what Francona called a stiff elbow after the game.

"But that was not a big enough deal to stop pitching," Matsuzaka said through translator Kenta Yamada.

Matsuzaka's turn was skipped after he came out of the bullpen on May 4 and pitched an inning of relief, taking the loss in a 13-inning, 5-3 defeat to the Los Angeles Angels. Four days later, he went six innings and was credited with the win in a 9-5 victory over the Minnesota Twins, but on Monday night he was dreadful, walking seven and giving up five hits in just 4 1/3 innings against the Orioles.

Matsuzaka acknowledged his velocity was down, and he was in pain. Data from Monday night's start show that his fastball averaged just under 88 mph, and he topped out at 89, according to BrooksBaseball.net. That's down 3-4 mph from what he has typically pitched.

"I couldn't throw as fast as before, but within this condition I tried to modify it,'' Matsuzaka said, according to Yamada's translation. "I was fortunate enough to win against Minnesota, but if I continue this pitching then I wouldn't help the team.

"In general, I could hold the pain and still throw before. But at this point, it's difficult to hold it with this kind of pain. So, I usually have a high tolerance, but this time it's hard for me to keep throwing."

Matsuzaka said he did not know at this stage whether he would pursue a second opinion.

"When I heard the result of the MRI, the condition was worse than I expected," he said. "About the time frame, I have about two weeks off, and I will see how the recovery process goes."

Asked if he was concerned that he might need surgery, he said no.

Right-hander Michael Bowden was recalled from Triple-A Pawtucket.

In each of the past two seasons, Matsuzaka had landed on the DL twice. Last year, he made only 25 starts because of neck strain and a strained right forearm.

In 2009, he made just 12 starts and pitched only 59 1/3 innings. He was sidelined with a strained shoulder early in the season and again with the same injury that June.

In 2008, Matsuzaka set a career-high with 18 wins despite missing some time with a strained rotator cuff.

Matsuzaka, for whom Boston paid $103 million ($51 million posting fee, plus $52 million contract) to acquire from Japan before the 2007 season, is in the fifth year of a six-year contract.

Gordon Edes covers the Red Sox for ESPNBoston.com. Information from ESPNBoston.com's Brendan Hall and The Associated Press contributed to this report.