Financial terms were not disclosed by the team, however multiple media outlets reported it was worth $12 million.
The contract reportedly will pay Martinez just $4.5 million in 2024, with the rest deferred to be paid $1.5 million annually from 2034-38. The deferrals will save the Mets significant money in terms of luxury tax.
Martinez was an All-Star for the third season in a row last year. In his lone season with the Los Angeles Dodgers, he hit .271 with a .321 on-base percentage, a .572 slugging percentage, 33 homers and 103 RBIs over 113 games in 2023.
"JD is a veteran major league player with a proven track record," said David Stearns, Mets president of baseball operations. "His valuable bat will provide protection and extend the lineup. His addition to the club continues our commitment to compete in 2024 and beyond."
To make room for Martinez, the Mets designated right-hander Phil Bickford for assignment.
Martinez lost his spot in Los Angeles when the team signed two-way star Shohei Ohtani, who will be limited to designated hitter duties for most or all of this year while recovering from an arm injury.
Martinez spent the previous five years in Boston, helping the Red Sox win the 2018 World Series, a year in which he led the majors with 130 RBIs.
He previously played for the Houston Astros (2011-13), Detroit Tigers (2014-17) and the Arizona Diamondbacks (2017). In 1,522 career games, he has a .287/.350/.524 batting line with 315 home runs and 1,002 RBIs.
Mark Vientos was the likely candidate to be the Mets' regular designated hitter before Martinez's arrival. Vientos, 24, hit .211/.253/.367 with nine homers and 22 RBIs in 65 games last year.
Bickford posted a 5-5 record with a 4.95 ERA in 61 relief appearances last season.
He owns an 11-8 record with a 4.43 ERA in 179 career relief appearances with the Milwaukee Brewers (2020-21), Dodgers (2021-23) and Mets.
The Mets are coming off a disappointing 75-87 season in 2023, when they had the major leagues' highest payroll.
