Red Sox's Beckett says lat soreness has lingered for a week

Two days after the Boston Red Sox chose to skip his turn in the rotation, right-hander Josh Beckett admitted the stiffness in his latissimus muscle predated his 126-pitch start last Sunday in Chicago.

"It's kind of been there for about a week, kind of leading into my last start," Beckett said Friday before the Red Sox lost 6-4 to the Baltimore Orioles in 13 innings at Fenway Park. "On your start day, you can always make yourself believe that things are better than they are. I really wanted to pitch. I just ended up making things worse."

In hindsight, manager Bobby Valentine also wished Beckett had spoken up sooner. Instead, he allowed Beckett to match his career-high pitch count, a number he hadn't reached since 2004 with the Florida Marlins.

"We have a system set up to have information flow. It just seemed like there was a little snag there," Valentine said. "It's not up to him to come into the manager's office, but you talk to the pitching coach all the time and the trainers all the time. That information usually flows up. In retrospect, it would've been nice to know that."

Beckett played catch from 90 feet Friday and said he felt better. The Red Sox don't expect him to miss more than one start, with general manager Ben Cherington noting that Beckett likely would make his next start if it were later in the season.

Initially scheduled to start Saturday, Beckett will be replaced by veteran right-hander Aaron Cook, called up late Thursday from Class AAA Pawtucket.