"He was a great member of the Red Sox team for seven years, and a certain Hall of Famer," Red Sox president Larry Lucchino told The Associated Press in an e-mail. "He will be missed, and we are disappointed to have lost him to the Mets and the National League."
Martinez's agent, Fernando Cuza, told the Mets he will attempt to work out a deal with them after New York guaranteed a fourth year, a person involved in the talks said on condition of anonymity.
"Nothing has happened yet," Martinez said from the Dominican Republic on Monday night.
Mets general manager Omar Minaya expressed confidence about the negotiations with Martinez but wouldn't detail the discussions.
"The good news is that we're still in dialogue," Minaya said. "Every day that goes by and we are having dialogue is a good day."
Minaya then left baseball's winter meetings and returned to New York, and the sides will work by telephone to finalize the contract language. The remaining issues are believed to revolve around perks the Red Sox had included in their offer, ESPN.com's Jayson Stark reports.
New York initially offered a $37.5 million, three-year contract with a $12.5 million team option for 2008.
Boston's final proposal was a $40.5 million, three-year deal that contained a club option for 2008, a baseball official said, also on condition of anonymity. The Red Sox thought the Mets' offer was for $56 million over four years, the official said, but a Mets official said that figure was not correct.
An agent who spoke with the Mets said New York's proposal was worth about $52 million.
"We put our best foot forward and made an offer that makes sense to the club," Red Sox general manager Theo Epstein said. "We think it's a fair and generous offer."
Martinez, 33, must pass a physical before the Mets complete the deal.
ESPN's Steve Phillips is reporting that one of the items under discussion between the Mets and Martinez's representatives is what specifically will be allowable in the right-hander's physical.
One item being discussed is whether Martinez would be allowed to skip any potential MRI exam as part of the physical and instead merely take a strength test on his arm and shoulder. Martinez has a history of arm injuries. As far back as 1999, Martinez was placed on the DL with right shoulder injuries; in 2001, Martinez feuded with Red Sox management as he claimed to have a slight tear in his right rotator cuff.
What is not yet known is whether the Mets have agreed to this stipulation.
Cuza did not want to comment on the talks.
"You are always asking the same thing, but I should tell you that when I sign, I will let you know all the details," Martinez told reporters Monday afternoon in the Dominican Republic, according to ESPN Deportes' Web site. "Not even I know about all this. People think that I know everything, but that is not true. You guys will be the first to know."
Martinez helped pitch Boston to its first World Series title since 1918, but Epstein said he refused to increase the team's offer in the past two days.
"We wish Pedro nothing but the best going forward both on the field and off the field," Boston owner John Henry said in an e-mail. "He pitched with every ounce of his being for the Red Sox over the course of 216 games. Some of those performances were among the most memorable in Red Sox history. Who will ever forget the 1999 All-Star Game? He has earned everything that he has accomplished, including his World Series ring and his reputation as one of the greatest who ever lived."
Landing Martinez would be the splashiest move made by the Mets since Minaya became general manager in late September. A six-time All-Star with Montreal and the Red Sox, Martinez has a 182-76 record and 2.71 ERA in a 13-year major-league career that began with Los Angeles in 1992. Minaya, who is also Dominican, visited Martinez in his homeland last month.
Martinez would join a Mets rotation that includes two-time Cy Young winner Tom Glavine, Kris Benson, Steve Trachsel and Victor Zambrano.
Glavine was surprised Martinez would leave a World Series winner but was happy with the decision.
"The more quality guys you have in your rotation, the more everybody feeds off everybody else," Glavine said. "All those years in Atlanta, you always had the pressure to keep up with everybody, but you knew if you had a bad game, you had the luxury of knowing somebody behind you would have a good game."
The Mets have slumped badly since losing to the Yankees in the 2000 World Series, finishing last in the NL East in 2002 and 2003 and then going 71-91 last season for their third straight losing record.
"We certainly can be in contention if all five guys in the rotation stay healthy and pitch up to their capability," Glavine said. "We'll be in position where every night we have a quality guy starting."
Minaya is also trying to add a position player, and there have been talks to acquire Sammy Sosa from the Chicago Cubs, possibly for Cliff Floyd.
"It certainly would be nice if we can add a bat or two," Glavine said.
Martinez's time in Boston was electrifying from the start, as he piled up the Cy Youngs and strikeouts and brought a Latin beat to Fenway Park. But he was also temperamental, complaining about contract negotiations and slights from a few fans among the thousands of admirers.
His departure leaves the Red Sox to defend their title with a rotation that currently includes Curt Schilling, David Wells, Tim Wakefield and Bronson Arroyo.
Derek Lowe, who became the first pitcher to win three postseason clinchers in one year, became a free agent.
Information from The Associated Press was used in this report.