FORT MYERS, Fla. -- Boston Red Sox general manager Theo Epstein told reporters on Wednesday morning that Daisuke Matsuzaka has what the team believes to be a mild back strain but that it would not prevent the pitcher from having a normal spring training.
Epstein said Matsuzaka suffered the mild strain on Friday and his throwing program would be delayed, but only slightly. As a precaution, Epstein said, Matsuzaka would not throw again until he receives a physical like the rest of the team's pitchers and catchers on Friday.
Red Sox manager Terry Francona offered a slightly different take later Wednesday morning, saying that Matsuzaka had soreness in both sides of his upper back and the injury actually occurred at the Athletes' Performance Institute in Arizona, where Matsuzaka worked out in the offseason.
"We already decided we were going to be kind of slow with him anyway," Francona said. "When that situation arose, we decided that physicals aren't going to be for another couple of days, there's no sense in having him throw sides -- we'll let the medical people get a little better handle on where we think he is and what's the best timetable for moving forward in the spring."
Epstein said Matsuzaka disclosed the back strain to the team and that his communication on the issue has been excellent.
"His attitude has been great. He was very accepting when we told him we want to treat it conservatively," Epstein said, as relayed by WEEI.com. "I know he's worked really hard this winter to make up for last year and come out and have a big season. That's what we're all hoping for him. We want to slow this thing down so we don't turn something small into something big. Last year, he never really was able to get into condition to pitch in part because of the way things went early in spring. We want to make sure we avoid a repeat of that."
Matsuzaka declined to talk to reporters on Wednesday.
Matsuzaka's health was a sensitive issue last season, when the Red Sox sent him back to Fort Myers in midseason because of a tired shoulder, brought on in part, they felt, because he was not in acceptable shape and exerted himself too much in the World Baseball Classic before the season. Matsuzaka also revealed after the season that he had injured his groin the previous January and did not inform the Red Sox of the injury, even though they inquired repeatedly about his health.
Epstein said earlier this week, however, that those issues were in the past and the team and Matsuzaka were on the same page. Francona said Matsuzaka looked great this spring after his offseason workouts in Arizona.
"He's done a terrific job, he looks like he's in great shape," Francona said. "He spent a lot of time working on it, which is what we wanted. I think he agreed with [the decision to shut him down for now]. We've come a long way in communicating how he feels, how we feel."
Matsuzaka had a horrendous start to last season, going 1-5 with an 8.23 ERA in his first eight starts before being shut down by the Red Sox in June. He bounced back strong after rehabbing the tired shoulder, going 3-1 in his final four regular starts in September and October with a 2.22 ERA.
"He's got something to prove," Epstein said earlier this week. "He wasn't healthy last year, so he needs to do what it takes to get ready for the season. He worked hard this winter, but that doesn't guarantee results on the field. I know it's important to him that he has a good year."
ESPNBoston.com's Gordon Edes contributed to this report.