It's official: Josh Beckett won't pitch tomorrow.

Given the events of the past few days, the Red Sox' announcement yesterday that Beckett will miss a start seemed inevitable. The veteran right-hander has been unable to throw a bullpen session since leaving Tuesday night's game in the third inning because of back spasms.

It remains unclear, however, when Beckett will pitch again.

Asked if Beckett will need to go on the 15-day disabled list, manager Bobby Valentine said it "seems unlikely," but characterized the situation as "kind of nebulous." Valentine added Beckett was feeling better yesterday, and general manager Ben Cherington said the Red Sox' training staff has reason to be confident Beckett will miss only one start.