Kevin Youkilis was introduced as a member of the Yankees on Friday (AP)

The development was certainly unexpected.

For years, Kevin Youkilis was among the most loathed visitors to Yankee Stadium. As a member of the Red Sox, he seemed the ultimate antagonist in the American League East rivalry, in some ways Boston’s answer to Yankee predecessor Paul O’Neill (a player to whom former Yankees manager Joe Torre sometimes compared Youkilis). If there was a bloodthirstiness to the rivalry, it seemed as if the Yankees (and their fans) wanted Youkilis’ blood more than any other player’s, with memorable instances in which Joba Chamberlain threw over Youkilis’ head and in which Scott Proctor once actually did send a fastball glancing off his helmet.

Given the side of the fault line on which he resided for the first eight-plus seasons of his big league career, then, it came as something of a shock even to Youkilis that he donned pinstripes on Friday for his introductory press conference as a member of the Yankees following his agreement to a one-year, $12 million deal to play for New York in 2013.

“I never thought I’d be on the other side of the rivalry,” Youkilis admitted to reporters in New York. “I was very humbled and amazed that the Yankees jumped into the picture.”

The Yankees’ pursuit of Youkilis commenced in earnest after it was announced that Alex Rodriguez would miss at least the first couple months of 2013 following hip surgery. When that happened, Youkilis represented not only the best free agent on the market, but also a player who would be amenable to a short-term deal (something critical for the Yankees given their desire to get under the luxury tax threshold of $189 million in 2014).

Youkilis posted the worst numbers of his career in 2012, hitting .235 with a .336 OBP, .409 slugging mark and .745 OPS in 122 games for the Red Sox and, after a June trade to Chicago for Zach Stewart and Brett Lillibridge, the White Sox. However, he still remained a power hitting threat, launching 19 homers, he posted strong numbers against left-handers (.275/.386/.492/.878) and continued to produce his characteristically grinding at-bats, averaging 4.25 pitches per plate appearance.

Given the absence in their lineup, the Yankees saw Youkilis as perhaps the best player capable of filling in for Rodriguez. Meanwhile, though Youkilis has spent his career playing the role of the villain in visits to the Bronx, he’s optimistic that his reception may enjoy a slight alteration in Yankee Stadium now that he will be wearing the home pinstripes.

“I’d guess they’re all going to sound the same,” Youkilis said at the press conference of the possibility of whether he’ll be cheered or booed. “It will be all mixed in, so I’m going to take it as they’re all saying, ‘Youk.’

“Over the years, I’ve had a lot of Yankee fans come up to me and say, ‘Hey, I’m a huge Yankees fan, but I like the way you play the game,’” he added. “I’m going to play as hard as I can every day 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.”