FORT MYERS, Fla. -- Aaron Cook will officially start his audition to be Boston's fifth starter when he works in relief of Jon Lester in Sunday's road game against the Orioles.

The 33-year-old righty has gone at a more conservative pace than the other pitchers because of his recent history of injuries. But when Cook is right, he can be an integral part of a pitching staff.

In 2008 he went 16-9 with a 3.96 ERA.

What will manager Bobby Valentine be expecting from Cook on Sunday?

"Sinker. Really look for his sinker," Valentine said. "He's been throwing it, and he feels good. It's his make-or-break pitch. We're going to see how it's sinking."

Can Cook catch up in time to be ready for the rotation at the start of the season?

"That may be an issue at some point," said pitching coach Bob McClure. "I don't want to rush him. I want him healthy, and so does he. He doesn't want to go backward, either. We'll just have to see on that. But I'm not going to rush him through it, because he's got a career still ahead of him."

Dice-K well on his way to a return to action

FORT MYERS, Fla. -- Daisuke Matsuzaka continues to impress the Red Sox in his comeback from Tommy John surgery, and there's no reason to think he can't rejoin the club by around midseason, perhaps even a little earlier.

The right-hander reeled off a 40-pitch bullpen session on Saturday under the watchful eye of pitching coach Bob McClure and assistant pitching coach Randy Niemann.

"It was 40 pitches total, where he threw 20 and we had him sit, like in the middle of an inning, and then do 20 more," McClure said. "As far as from what I'm seeing, from a health standpoint it was hard to tell he was ever even hurt from the way he's throwing the baseball right now. That doesn't mean he's ready by any means. I'm just saying it's free and easy, it's coming out of his hand really good. It's clean, it looks sharp. It looks like he's on schedule."

Spring Training
• Spring Training schedule

Things are progressing so well for Matsuzaka that he's been able to spend a lot of time of his time during camp working on mechanics.

McClure thinks the adjustments could be vital in that they could lessen the stress on Matsuzaka's arm and reduce the risk of further injury.

"We're really dealing with some issues as far as a mechanical standpoint in order to get his body in the right position so this doesn't happen again," McClure said. "There's a little bit from the rehab where he got into some bad habits. Randy Niemann and myself are trying to correct those bad habits and have him to where he was before he got hurt."

The way McClure explains it, the issue is for Matsuzaka to keep his delivery more compact and not allow his head to rotate out of proper position.

Aceves has become indispensable to Sox

FORT MYERS, Fla. -- It seems almost unfathomable that at this time a year ago, Alfredo Aceves was battling just to make the team. And it's even harder to believe that he was initially unsuccessful in that quest, serving two stints at Triple-A before joining the Red Sox for good on May 6.

These days, Aceves is considered indispensable.

He certainly looked it on Saturday night, firing three shutout innings against the Rays in a 5-0 win.

"From what I've seen, he may be one of our best pitchers," said pitching coach Bob McClure. "I'm not talking about throwers. I'm not talking about stuff. But from a pitching standpoint, he's very advanced as far as knowing what to do and when to do it and commanding a baseball at all different speeds."

Though Aceves pitched in relief of Daniel Bard on Saturday, he is very much in the mix to win a spot in the rotation. If he doesn't he becomes what he was last year -- an invaluable pitcher out of the bullpen.

"He's someone we have to really seriously look at as a possible guy in that starting rotation," McClure said.

"He had everyone off balance, mixed his pitches, had great movement, looked like good location," said manager Bobby Valentine.

If the job was awarded solely on ability, Aceves would probably win the fifth spot. The real question is whether the bullpen would have enough to cover for his absence.

"I think the front office has done a very good thing as far as signing guys that are capable of possibly doing that, but there's so many guys vying for the fourth and fifth spot right now, it's a little different," said McClure. "We have [Felix] Doubront, who's vying for a starting spot, who might be able to do the same thing, but he's younger. There's [Vicente] Padilla, who's in the mix as a starter but might be able to do the same thing. It's a puzzle that I haven't quite figured out yet."

Every spring outing a milestone for Bard

FORT MYERS, Fla. -- Just by the nature of Daniel Bard's goal of moving from the bullpen to the rotation, he is pretty much going to reach a milestone each time he pitches this Spring Training.

Saturday marked the first time he reeled off three innings in a game since 2007, when he was a down-on-his-luck starter just trying to survive in the Minor Leagues.

This time the occasion was far more satisfying. Bard not only went three innings, he prospered, holding the Rays to two hits and no runs in a 5-0 win. He fired 49 pitches, 30 for strikes.

"I really didn't feel much different," Bard said. "My body feels good. I felt like I had more pitches in me again. Hopefully, that keeps up. I'm sure I'll hit some kind of ceiling and start to feel the fatigue, but it was good."

Unlike his first Grapefruit League start earlier this week, Bard incorporated a third pitch into his mix -- the changeup. In fact, he threw a bunch of them.

"It was probably around 12 or so," he said. "I didn't count, but I know that was something we talked about before the outing, using that pitch and using it in some different counts. I only threw a few sliders. For the most part, that was my offspeed pitch today."

Though the general perception is that Bard will win the fourth spot in the rotation, with the fifth spot the only one up for grabs, it is still a competition in his mind.

"I know I have a spot on the team, but my role's up in the air," he said. "I do feel like I have things to prove. That definitely gives me the motivation and tells me that these games mean something, because they do mean something to me."

And they mean something to those who are monitoring him as well.

"He doesn't have to prove anything," said pitching coach Bob McClure. "Basically, what I'd like to see is the ability to repeat his delivery. He doesn't have to be perfect, because his stuff is plus. [He needs] the ability to throw his offspeed in any count. The advancement of his changeup could be a huge pitch for him. There's a lot of things. It's not really proof. It's, 'Is he there yet?' He's going to get enough starts in Spring Training to see if he's ready for that."

Bobby V not a fan of pitching out of windup

FORT MYERS, Fla. -- As legend has it, manager Bobby Valentine created the wrap sandwich. By contrast, he'd like to "de-create" pitching out of the windup.

Yes, Valentine is of the belief that pitchers should throw out of the stretch all the time. He knows that it might never happen in his lifetime, but he still believes in it.

"I'm not a believer in the windup, period. I don't get it. You throw your most important pitches of the game out of the stretch, so you have to be more effective out of the stretch," Valentine said. "Men are on base when you're pitching out of the stretch, so if that's where you can throw your best pitches, why are you teaching yourself to throw twice, two different ways?

"It's a crazy thought, but I think if we were just starting the game right now, we wouldn't teach anybody a windup. You could break a hitter's rhythm with your stretch if there's no one on base. You could quick pitch, quick step, you could have a big step. You're always in the same cadence out of the windup. It's the easiest thing for a hitter to time. And it's difficult. There's a lot of moving parts.

"Take a guy like Daniel Bard, who throws 100 miles an hour out of the stretch. Is he going to throw 106 out of the windup? Probably not. But I know it's not going to happen. Another lifetime, it will all come to pass."

Valentine served two managerial stints in Japan, and he said it's commonplace there for starters to work exclusively out of the stretch.

"[Hideo] Nomo pitched a no-hitter at Coors Field out of a stretch. You know?" he said. "[Yu] Darvish might not pitch out of a windup [this season]. He doesn't necessarily need it.

"It's just one of those things. Just another stupid statement late at night. Somebody will say, 'Can you believe that idiot said that?'"