Utility man Pedro Ciriaco has been selected from Triple-A Pawtucket to take over the second baseman's spot on the active roster. Lefty Rich Hill was moved to the 60-day disabled list to make room for Ciraco on the 40-man roster.
The Red Sox will be without perhaps their most invaluable player until at least July 19, the first day Pedroia is eligible to return.
Pedroia will wear a protective cast for the next two weeks, obviously limiting him from doing most -- if not all -- baseball activities over that span.
"It's just frustrating because I healed it up from the other injury and was just starting to feel better and swing the bat better, and I dive one time and now this," Pedroia said. "It's just frustrating, but the guys, we'll hold it down. We're getting our other guys back, and I'll be back soon, so we'll make our run."
Injuries to key players have become a way of life for the 2012 Red Sox. Carl Crawford, who could return right after next week's All-Star break, hasn't played at all this season. Neither has closer Andrew Bailey, who is coming off right thumb surgery.
Outfielder Jacoby Ellsbury, who finished second in the American League Most Valuable Player Award voting last season, hasn't played since April 13. Josh Beckett also spent time on the disabled list, and another key member of the rotation -- righty Clay Buchholz -- has been sidelined since June 19.
"We'll be fine," said Pedroia. "We'll have guys step up. We're going to have some other guys get back here pretty soon. Guys are going to have to step up and play good baseball. I'll be back in a few weeks. It's not like I'm going to be out all year, so guys will weather the storm and we'll be fine."
The Red Sox were 42-40 and 7 1/2 games back in the AL East on Friday entering a four-game series against the first-place Yankees.
Pedroia has been bothered by soreness in his right thumb since mid-May and had been diagnosed with a torn adductor muscle. He was out of action from May 29-June 4.
It had been clear since Pedroia returned from his initial thumb injury that it was still an issue. Since June 5, Pedroia is hitting .210 with one homer, 12 RBIs and a .282 on-base percentage. Without question, he is having a below-par season, hitting .266 with six homers and 33 RBIs.
But on July 1 in Seattle, Pedroia hit a game-tying homer in the eighth inning and had a key single during the 10th. The next day in Oakland, he had two more hits.
Then came the dive on Tuesday, putting Pedroia back to square one.
"I was just starting to drive the ball, hit the ball in the air to both sides and using my hands," Pedroia said. "That's the part that I have trouble dealing with. I played that month hurt, and to finally get healthy, and dive and get hurt again. ... But I'll be fine. It happens for a reason. I'll be back."
Pedroia has faith that his healing power will serve him well again.
"I'm a lizard," quipped Pedroia. "I heal while I play. I'm a freak healer. I heal great."
If the Red Sox can make a run in the second half, Pedroia hopes he will be a central part of it.
"You work so hard in the offseason to prevent injury, and you get a couple of freak accidents, same thumb; it stinks," Pedroia said. "I'll be fine. I'll produce in a major way this season to help our team -- I promise you guys that."
Manager Bobby Valentine doesn't doubt it.
"I'm hoping he comes back as good as he's ever been," Valentine said. "He's been a click away most all of the year from being the MVP-type player that he has been, and maybe this little step back will get him that step forward that he needs."