BOSTON -- Reliever Andrew Bailey had a setback in his throwing program during a bullpen session on Friday as he continues to rehab from offseason thumb surgery. As a result, the Red Sox will slow down his progression.

Bailey felt tightness in his arm when he threw off the mound prior to Friday's game vs. the Braves.

"Getting back on the mound, you get that kind of Spring Training tightness," Bailey said. "Nothing urgent. Just kind of, I don't know, nothing I've ever had before, or any pitcher has ever experienced. For us, before we take that next step, maybe throw another bullpen [session] or two and then we'll go from there."

The right-hander had been ahead of the curve in his rehab before Friday's setback.

"It didn't go perfectly," said manager Bobby Valentine. "We're going to let him rest a little before he gets back on the mound. His arm didn't feel great throwing. We were accelerating his progress a little and we decided to slow it down."

So how does the thumb feel?

"Thumb's feeling great. That rehab went really well," said Bailey, who has not pitched for Boston this year. "Now it's about getting the arm in shape as well."

The next time Bailey throws it will be from flat ground.

"I need to just be confident in letting it loose before I go face hitters or anything," he said. "Nothing urgent. It just takes some more time. We've got a lot of season left. I've got to be able to help the team, healthy and confident. That's what I've got to do."

Crawford walks twice, hitless in first rehab game

BOSTON -- Carl Crawford played in an organized game for the first time this year, starting his 20-day Minor League rehab assignment with the Gulf Coast League Red Sox on Saturday.

In five plate appearances as the designated hitter, Crawford went 0-for-3 with two walks and a run scored. He grounded out to second twice and flied out to center.

"His legs were still underneath him at the end of the game, he felt pretty good," said manager Bobby Valentine.

Crawford had left wrist surgery in the offseason and was diagnosed with a sprained UCL in his left elbow in April. The GCL Red Sox are off on Sunday and Crawford will likely DH again on Monday.

"He's going to maybe play in the field on Monday or DH on Monday, probably DH again," Valentine said.

So when will Crawford play in the outfield?

"I think next week sometime," the manager said. "[We'll decide] as it progresses."

The Red Sox are unsure when Crawford will advance past the GCL for rehab games at a higher Minor League level.

"When he's ready to move he'll move," said Valentine, who has yet to manage the outfielder. "We really can't put a timetable on that. It's a more controlled environment [in the GCL] and we want to make sure we control it as much as possible."

Another injured outfielder, Jacoby Ellsbury, took batting practice on the field before Saturday's game vs. the Braves. He also fielded ground balls in the outfield. He partially dislocated his right shoulder on April 13.

So what remains for Ellsbury before he can begin a rehab assignment?

"He needs to throw more, he needs to be confident that he can get back to bases and dive, things like that that are shoulder related," Valentine said. "And swing more."