In the face of a serious challenge from the Yankees, Boston has improved their contract offer to Pedro Martinez, writes the Boston Globe’s Bob Hoehler.

A source close to the talks indicated the Sox made an effort to satisfy Martinez’s desire for a guaranteed three-year contract without specifically making the guarantee. Instead, their latest proposal included unspecified language that Sox officials believed would increase the deal’s potential value enough to make it far more attractive — and hopefully acceptable — to Martinez. He is believed to be seeking a deal that effectively guarantees him at least $40 million over three years.

Sox officials declined to discuss details of the latest offer, which was described as unusually complex. But the team has creatively used a number of contractual techniques to sweeten deals to the satisfaction of star players. The techniques have included significantly lowering the threshold for performance bonuses and offering innovative escalator clauses, such as Curt Schilling’s $2 million provision for helping to win the World Series.

Though Martinez has yet to be persuaded by the most recent offer — and no deal appeared imminent — the proposal proved sufficient enough to keep the talks alive.

The Sox initially offered Martinez $25.5 million over two years with a $13 million option for 2007 and $2 million in potential bonuses. With Martinez intent on securing the third guaranteed year, the Sox altered their proposal to make the total $40.5 million value of the deal more easily attainable.

Still, Martinez continued shopping for a better deal, even as another Yankee all but invited him to join him in the Bronx.

“I’ve been in the majors for 10 years, and for me the best pitcher I’ve seen is Pedro Martinez,” Alex Rodriguez said in a television interview in the Dominican Republic, according to the Associated Press. “He is a genius with the ball, has incredible discipline and knowledge of baseball. I love him and respect him a lot.”

High praise coming from a former teammate of Randy Johnson and opponent of Roger Clemens. Or, perhaps, effortless hyberbole from a guy whose public statements aren’t exactly oozing with sincerity.