A person with knowledge of the deal says the Pirates have agreed to a $17 million, two-year contract with the three-time All-Star, hoping he can give them some pop at the plate and respectable defence behind it.
The deal is pending a physical. The person spoke Thursday night on condition of anonymity because the contract had not been announced.
The agreement was first reported by Fox Sports.
"I want to thank the (at)yankees organization and fans for treating me with class and respect... I will truly miss the city and people of NY," Martin posted on his Twitter account late Thursday.
The 29-year-old native of Chelsea, Que., hit .211 with 21 homers and 53 RBIs in 133 games last year with the Yankees, who had been concentrating on bringing back some of their free-agent pitchers so far this winter. Martin's batting average has declined in each of the last five seasons after he hit .293 and made his first All-Star game while playing for the Los Angeles Dodgers in 2007.
The signing reunites Martin with right-hander A.J. Burnett. The two played together with the Yankees in 2011 before Burnett was traded to Pittsburgh last spring.
The Pirates were in need of an experienced backstop after declining the club option on Rod Barajas, who struggled in his one season in black-and-gold. Barajas hit .206 with 11 homers in 104 games and struggled defensively, throwing out just 6 per cent (6 of 99) potential base stealers.
Backup Mike McKenry fared better but neither have Martin's resume. Martin threw out 25 per cent (20 of 83) base stealers last season and committed just six errors in 128 games at catcher, the same total Barajas had in 24 fewer appearances.
The signing is the latest dip into deeper pockets by Pittsburgh, who went 79-83 in 2012, tied for the franchise's best record in the last 20 years. The season was marred by a late fade in which the Pirates fell from playoff contention but the team opted to not make any major changes to the front office and instead focus on upgrading several spots, with catcher being among the top priorities.