Brace yourself for the inevitable Gillette advertisement.

From Newsday’s Jon Heyman and Ken Davidoff. (thanks to Maura Johnston for the link)

In a development that may stun followers of baseball’s greatest rivalry, Boston’s beloved Johnny Damon agreed Tuesday night to jump ship and join the hated Yankees, Newsday has learned.

Damon and the Yankees were putting the finishing touches on a four-year, $52-million contract, according to multiple sources. The Damon deal is contingent upon him passing a physical, but considering he’s never spent a day on the disabled list, there’s no concern there.

The Yankees have been insistent all along that they would not go beyond four years for the 32-year-old Damon, and they may have surprised themselves by accomplishing their mission without wrecking their plan. Their concession was to pay Damon $13 million annually, which is actually slightly above his original asking price of $12 million. Damon is also to receive a no-trade clause as part of the deal.

(postscript : The Globe’s Gordon Edes quotes Damon as saying the following on Boston’s CBS outlet earlier tonight ;

“(The Yankees) came after me aggressively. We knew George Steinbrenner’s reputation. He wants to have the best players .. (I’m) now part of the Yankees with a great lineup. We’re going to be tough to beat.

œNo, (the Red Sox did not match the offer), I talked to Tito (Francona) and I told him they had to ‘really get going’ ¦ (I) had other plans, I’m not sure if they knew I meant it but I’m a Yankee. Hopefully now they’ll go off and get one of the center fielders they’ve been courting for the last month or so.

“Our policy with the Yankees is to go out there and win¦ Good leadoff men are tough to find and I think the Yankees found the best leadoff hitter in the game.

“(Red Sox) fans are going to be upset. I hope they remember the great World Series and the three out of four years we made the playoffs. I appreciate them¦ I tried to come back.

It remains to be seen, of course, whether or not the Red Sox can obtain Coco Crisp from Cleveland, and if successful doing so, the Boston equipment manager has a fake beard and wig at the ready.)