BOSTON -- Not only did the Red Sox lose a heartbreaking 17-inning marathon to the Orioles on Sunday afternoon, but they were again left to wonder what has happened to Clay Buchholz, who seemed on the verge of becoming an ace not so long ago.

The start to this season has been a nightmare for Buchholz. He has pitched six times, and given up five runs or more every time out.

Buchholz is the first Red Sox starter since Red Ruffing in 1925 to give up five earned runs or more in six consecutive starts.

After the excruciating loss, manager Bobby Valentine wasn't ready to proclaim that Buchholz needs to take a break from the starting rotation.

But Valentine had a lot on his mind. He needed to use seven relievers in the loss, and his team is in the midst of a 20-game, 20-day stretch.

"Yeah, there were a lot of pitchers used today," Valentine said. "[Buchholz] was one of them and I've got to figure out what to do -- and how to get by with all these guys who really did a yeomen's job today. I have no plans to change [Buchholz's role] at this time."

What plagued Buchholz this time?

"Clay's performance was not what he wanted it to be for sure, and not what I wanted it to be," Valentine said. "He left a lot of pitches in a real hittable zone and gave up a lot of hard-hit balls."

After getting tagged for seven hits, five runs and three homers over 3 2/3 innings, Buchholz's ERA swelled to 9.09. Somehow, his record is 3-1.

"I've been upset at myself for the last six weeks," Buchholz said. "It's just frustrating to go out there and make some good pitches and still get hit. The game's not easy. That's the thing I have to keep telling myself. It's not that easy. It looks easy for some guys. Sometimes you've got to go through some struggles to get where you want to be. That's where I'm at right now. I've just got to find a way through it."

Middlebrooks' first MLB home run is grand

BOSTON -- The baseball soared off his bat and not only cleared the Green Monster, but it landed in the parking loss across the street. Will Middlebrooks struck his first Major League home run on Sunday afternoon at Fenway Park, and it was a grand slam.

Not only that, but his fifth-inning missile was a game-tying grand slam, serving as a memorable highlight in Boston's 9-6, 17-inning loss to the Orioles.

Middlebrooks, Boston's top position prospect, is manning third base while Kevin Youkilis heals his ailing back.

"It was probably the biggest rush of my life, to be honest," said Middlebrooks. "It was a grand slam and it tied the game up, which was huge."

And yes, somehow the baseball Middlebrooks drilled was tracked down by a dutiful Red Sox employee.

"A security guard got it for me in the parking lot. It's something I can put on the mantel for sure," Middlebrooks said.

There was only one blemish on the day for Middlebrooks. In the bottom of the 11th, with two outs, he smoked one down the left-field line. The ball caromed off the wall, but Middlebrooks was left with a single.

"That ball comes back in this ballpark," said Red Sox manager Bobby Valentine. "It kind of starts foul and then gets blown back. He'll run next time. That's for sure. He was very surprised that ball came back. After you see it once or twice, you're not surprised anymore. It starts foul and comes back here."

Cook placed on DL after tough start, collision

BOSTON -- With 11 stitches in his left knee, Aaron Cook was placed on the disabled list on Sunday, one day after he was spiked in a collision at home plate.

Cook was making his debut for the Red Sox when the incident occurred. He stayed in the game, but he was shelled (2 2/3 innings, eight hits, six earned runs) and removed shortly thereafter.

To replace Cook on the roster, Boston summoned lefty Andrew Miller from Triple-A Pawtucket, where he had been in the final days of a rehab assignment.

"We need a little help in the bullpen, obviously," said manager Bobby Valentine. "So Aaron understands that. He understands baseball. [Plus], he has 11 stitches, and I can't try to have him pitch. He's had shoulder problems in the past. If the stitches come out, there could be infections. It's the only thing we can do at this time, I think. He'd like to pitch. But it's not going to happen."

Cook didn't have a defined role on the pitching staff. He was filling in for Josh Beckett for just one start while the ace righty battles a lat injury.

Miller, who pitched for the Red Sox in 2011 as both a starter and reliever, opened the season on the DL with a strained left hamstring.

He was used exclusively as a reliever at Pawtucket, where he posted a 5.73 ERA in 10 outings.

"I've been throwing the ball well," said Miller. "It took a while to get back up here. I feel like I used up almost every day available [of the 30-day rehab], but I'm up to help contribute."

Miller becomes the third lefty in Boston's bullpen, joining Franklin Morales and Rich Hill.

"He'll be our first left-hander out of the bullpen, and I'd like it to begin with getting left-handed hitters out," said Valentine.

Youk making progress; return date still uncertain

BOSTON -- Sometimes you need to walk before you can run, and that's how the Red Sox are proceeding with Kevin Youkilis as he recovers from a lower back strain.

"Youk's going to start a walking program today," said manager Bobby Valentine. "I mean, he's walking. But as they explained it to me, [he'll be moving] probably backward and forward and getting into the pelvic movement that's needed. He's progressing. He'll stay back and not come with us [to Kansas City], because he doesn't need the plane ride for his back and he has rehab being done here."

The first day Youkilis is eligible to return from the disabled list is May 14, when the Red Sox open a two-game series at home against the Mariners. Will he be ready by then?

"Again, it's tough to put the clock on an injury," Valentine said. "When Youk's ready, he'll definitely let us know."

In the meantime, highly touted prospect Will Middlebrooks will continue to start at third base. Middlebrooks missed Saturday's game with cramps in his left hamstring but returned to action on Sunday.