BOSTON (AP) – Red Sox pitcher Daisuke Matsuzaka will skip his next turn in the rotation while the team tries to figure out what’s wrong with him.

Matsuzaka’s day to pitch would have been Thursday, but that’s also the day John Smoltz is scheduled to make his return from rehab. Boston manager Terry Francona said Saturday that Matsuzaka will have a medical exam to see if there is anything physically wrong with him.

“We have some decisions to make on our rotation,” Francona said. “What we decided on going forward is he’s not going to make his next start.”

Matsuzaka was 18-3 with a 2.90 ERA last season, his second in the majors after a whirlwind courtship that required the Red Sox to pay $51.11 million for the right to negotiate with the Japanese star and another $52 million for a six-year contract. But he is 1-5 with an 8.23 ERA this year after failing to get an out in the fifth inning Friday night and taking the loss.

Francona said he stayed late at the ballpark Friday night, meeting with general manager Theo Epstein and pitching coach John Farrell. Before Saturday’s game against Atlanta, Francona spoke to Matsuzaka.

“He came in, and when we told him it became kind of obvious,” Francona said. “It was a very good meeting. We needed to get him looked at.”

Matsuzaka was the MVP of the World Baseball Classic this spring for the second straight time after going 3-0 with a 2.45 ERA in 14 2-3 innings over three starts.

Francona said Matsuzaka wasn’t the same pitcher when he returned to Red Sox spring training.

“It all started with the WBC,” Francona said. “It’s become obvious that his velocity wasn’t what it was.”

Smoltz, who hasn’t started since April 27, 2008, has run the clock out on his rehab and was waiting for a spot in the Red Sox rotation. The team had talked about going to a six-man staff until the All-Star break, but now Smoltz will slide into Matsuzaka’s spot.

“As far as the rotation, that’s not something I’ve ever been shook up about,” Francona said. “I’ve never been bothered by having too much pitching.”

AP-ES-06-20-09 1830EDT