Even Kevin Youkilis admitted that the idea seemed odd at first. "I never thought I'd be on the other side of the rivalry,'' he said.

But the more he talked it over with his family, the more he warmed to the idea, which is why the former Red Sox mainstay agreed to a one-year, $12-million contract to join the Yankees. The deal was made official Friday.

"All the things that were happening, all the different options out there, we just felt that the New York Yankees were the best fit going forward to try to win another World Series,'' Youkilis said in a conference call with reporters.

The Indians reportedly had offered Youkilis a two-year deal, with the added bonus of reuniting with former Red Sox manager Terry Francona. But Youkilis said the allure of competing in the postseason and the chance to experience playing in New York swayed his decision.

Youkilis, 33, will fill in at third base for Alex Rodriguez, who might not return until midseason. Rodriguez is scheduled to undergo hip surgery in January.

"The expectation is that Alex will come back,'' general manager Brian Cashman said. "But I have no guarantee or anything of that nature either.''

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Youkilis is a lifetime .283 hitter with 148 homers in nine seasons spent mostly with the Red Sox, but he is coming off one of his worst seasons. The Red Sox traded him to the White Sox in June and Youkilis finished the year hitting only .235 in 122 games.

Youkilis spent time on the disabled list with a lower back injury in 2012 and a sports hernia in 2011, although he says he's healthy. The Yankees believe he can step in for Rodriguez, and he also can be used at first base and designated hitter.

"I'm going to play as hard as I can every day,'' he said, "and I think a lot of fans will appreciate that. So that's all I can bring to the table and I hope that the Yankee fans enjoy watching me play.''

Youkilis already has taken steps to ease his transition to the other side of the Yankees-Red Sox rivalry. He reached out to outfielder Johnny Damon, who made a similar transition. Youkilis also plans to return the call of Yankees reliever Joba Chamberlain, who left him a voicemail this week.

Youkilis, who has had to duck numerous high-and-tight pitches from Chamberlain, played down the bad blood in the past between them.

"If it was that big of a deal, I wouldn't be signing with the Yankees,'' Youkilis said. "But I don't think it's that big of a deal.''

With Youkilis officially on the roster, the Yankees are likely to add another righthanded bat for the outfield. Meanwhile, the team is close to finishing details on a new two-year deal for Ichiro Suzuki.