Doubront, on the 15-day disabled list with a right knee contusion, is set to start Sunday against the Royals at Fenway Park. The lefty hasn't pitched since Aug. 9 in Cleveland.
The righty Matsuzaka, meanwhile, will start on Monday, possibly for the Major League club against the Royals, but most likely for Triple-A Pawtucket.
"He'll pitch Monday -- not here, necessarily," manager Bobby Valentine said. "He has a bullpen [session]. [Aaron] Cook has a bullpen. We have [projected Saturday starter Josh Beckett] going out there. There's a lot of things going on. Unless we just want to start some stir on something, I don't think there's any reason to even talk about it. Last time I looked, Kansas City doesn't need it."
Valentine later added Dice-K would "probably" be in Triple-A. Dice-K hasn't thrown in the Majors since July 2. If he pitches for Pawtucket on Monday, it presumably would be his last Minor League start because his rehab clock expires Tuesday. He's coming back from a strained trapezius.
Valentine appeared confused -- possibly in jest -- by the level of attention reporters were paying to the rotation.
"Why is there such a ... who cares who's pitching?" he said. "Why is this such a big thing?"