"It just tightened up and cramped up," said Youkilis. "They just took me out for precautionary measures. It's fine now. I iced it, it will be fine. I'll be ready to play [Monday]."
Youkilis said that X-rays taken after the game proved to be negative.
"Nothing. It got me right in the meat of the forearm," Youkilis said. "Any time you get it there, it just cramps up."
The Red Sox can ill-afford to have another infielder banged up. As it was, Youkilis moved to third base on Sunday so that Mike Lowell (left hamstring) could get a day off. Second baseman Mark Loretta (left foot) was replaced at second base by Alex Cora.
"I'm just trying to take all the factors into consideration and I just don't want Lowell limping through the next two weeks," said Red Sox manager Terry Francona. "I know [he'd] play."
Which is why Francona made sure not to give him the option. The same goes for Loretta, who was hit on the left foot by a pitch earlier in the week in Toronto.
"I can see him, favoring is not the right word, [but] I know he's hurting," Francona said. "I just kind of took it out of his hands and said, 'You know what, you're not gonna play today.' When they bring in that lefty later on, maybe we'll get him an at-bat."
Lowell went to third base in the eighth to replace Youkilis. Loretta wasn't needed in the victory.
Pitching plans: The Red Sox aren't ready to make any announcements, but Francona said preparation was well under way to determine who will pitch the second game of Saturday's doubleheader against the Rangers. Josh Beckett is pitching the first game.
Don't rule out prized prospect Jon Lester making his Major League debut in that nightcap. Lester's next start for Triple-A Pawtucket is scheduled for Monday, which would put him right on line to go again on Saturday. In 10 starts for Pawtucket, Lester is 3-4 with a 2.95 ERA.
The Sox also might need to find a starter for Sunday, as it's looking less likely that David Wells (bruised right knee) will be able to come off the disabled list that day.
"He's not been able to throw," said Francona. "We really were holding out hope [for] Sunday, but I don't know how realistic that is, because he hasn't been throwing."
Kapler report: Francona was in the process of playing phone tag with outfielder Gabe Kapler, who is in Florida at extended Spring Training. But from what the manager has heard second-hand, Kapler is progressing well in a key stage of his comeback from a ruptured Achilles tendon.
"He talked to [first-base coach Bill Haselman] and he said he had a good day," Francona said. "His legs felt a little heavy because of the workload, not his Achilles. I think he said he had good at-bats and felt good about his day and everything like that."
In the next few days, Kapler will advance to a Minor League affiliate.
Foulke gets rest: Wondering why Francona did not use right-hander Keith Foulke in the first two games of this series?
"His back is a little tight," Francona said. "Every time his back has been a little tight and we've run him out there, then we lose him for a week. I've seen it in Oakland, I've seen it here. We're trying to stay away from that. It happens all the time, and if we don't handle it appropriately, we lose him for too long."
Savior: How good has Jonathan Papelbon been for the Red Sox? Team stats maven Peter Chase pointed out just how good with a telling note on Sunday. Since the advent of the save rule in 1969, Papelbon is just one of 10 pitchers to have 20 saves as of June 4, and only the second to have a 100 percent success rate.
The only other closer to pull that off was Hall of Famer Dennis Eckersley, who was 20-for-20 on June 4 during his American League MVP- and Cy Young Award-winning season of 1992.
Coming up: Beckett opens up a four-game showdown at Yankee Stadium on Monday at 7:05 p.m. ET. It could be a memorable duel, with the Yankees sending Mike Mussina to the mound.