But the Red Sox announced that there will be one more Minor League rehab start on Wednesday for the right-hander before he re-joins the Boston rotation for the stretch run.
"Physically, I think that I'm in a good spot and I think I'm ready to come back right now," Matsuzaka said through interpreter Masa Hoshino. "Since going on the DL this time around, we've moved at a very conservative pace and there's no need to rush things right now at the tail end of it all. I'm going to get one more game, hopefully get some more pitches and some more innings and some more work in at the Minor League level. That's a decision that's been made by the ballclub and I'm prepared to follow it."
Before formalizing that Matsuzaka would pitch once more in the Minors, the Red Sox simply needed to make sure Tim Wakefield came through Saturday's start in decent health. It appears that was the case.
"I think he feels like he pitched with a bad back," Red Sox manager Terry Francona said on Sunday. "I think, obviously, the rest of the way out, we're kind of day to day with Wake. We'll keep an eye on him and see how he's doing and check in with him and check in with the trainers. Try to use days off to our advantage and things like that. That's about the best we can do."
As long as there are no further setbacks, Wakefield will make his next start on Friday at home against the Rays.
Matsuzaka's last Minors start will come in a playoff game for either Class A Greenville or Salem, depending on which logistical location winds up most convenient. The right-hander threw a side session in Chicago before Sunday's game against the White Sox.
Matsuzaka threw 67 pitches for Triple-A Pawtucket in his third rehab outing.
"Yeah, endurance, and we'd like to let him go significantly into the game," said Francona. "Just kind of see where he's at and get a little fatigued and pitch like that. We've been pretty upfront with him, and I guess with you guys all along that there's a reason we did this. It was with the big picture in mind. To deviate from that now, I think, would be a mistake."
Dice-K had no qualms with the club's thinking.
"If there's anything that I was concerned about it, it is that I haven't really gone deep into a game yet," Matsuzaka said. "I think I'm going to take this Minor League start as an opportunity to do that."
Matsuzaka could return to Boston's rotation as early as Sept. 15, when the Sox open a three-game series against the Angels.
"Everyone here has been pitching through their fatigue and their wear and tear here throughout the season and even though it was called rehab, I've been given a lot of down time so I don't know yet exactly how much I'll be able to throw when I do come back," said Matsuzaka. "But I'd like to make up for that down time by working really hard and doing my best."
As far as Wakefield is concerned, the Red Sox know that they can no longer plot out anything long-term down the stretch for the knuckleballer. There will be no magical cure for his back until he undergoes a surgical procedure to remove the loose bone fragment that is causing the discomfort.
"He doesn't ever short-change you on effort," Francona said. "Everybody that's been around him knows that. It's hard to watch him get over to first like [in Saturday's game], because you feel bad. But he says he really doesn't hurt as much as it looks, so that's good. He's, obviously, weak and I'm sure he is in some pain."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.