Youkilis, who was hit in the ribs by a Steve Cishek fastball on Tuesday, was said by Red Sox manager Bobby Valentine to be "rotationally restricted" and that the Marlins' team doctors would soon administer X-rays.
Youkilis raised his eyebrows when that report was relayed to him.
"I don't think I need them," he said, adding he feels ready to pinch-hit if called upon tonight. "It's below the ribs. It's more muscle. Not anything like that."
Youkilis, who has been hit by four pitches this year and more than anyone in Red Sox history (86), said Cishek got him good. "That was one of the better ones," he said.
MIDDLEBROOKS GROWN UP: Middlebrooks is second among American League rookies in batting average (.300), OBP (.339), slugging percentage (.508) and homers (6, tied) since his May 2 debut.
"He's done with the development stage," Valentine said.
Despite his performance, Middlebrooks hasn't found a permanent place in the lineup. He has sat for six of Boston's last 16 games.
"You have to be strong-minded," Valentine said. "If I saw any elevated frustration level or decline in performance, we'd have to make another decision."
As a rookie in 2004, Youkilis had a similar route as Middlebrooks. "He's doing great," Youkilis said. "It's not easy. I played like that for a month and a half. I was getting spot [duty], little things -- maybe. You pinch-hit here and there, you never get into a rhythm. It's hard.
"I think he'll be a good player in Boston," Youkilis said.
Valentine said he met with Middlebrooks when he was called up and tried to set his mind right.
"I told him to fasten his seatbelt," Valentine said. "This is life in the big leagues, you're doing great, I believe in you. All that good stuff. Those are just words. Until you experience it, it means nothing."
INJURY REPORT: Valentine said Daniel Nava (hand) is 'better' and could be available tonight, though he hasn't taken batting practice.
Carl Crawford threw from 60 feet in the outfield. He hit yesterday on the field. He will travel with the team to Chicago. Crawford was originally slated for Fort Myers on Thursday.
Jacoby Ellsbury will head to Fort Myers.
Cody Ross was sore after today's workout, but is still on track to complete a three-game rehab assignment in Buffalo this weekend.