The deal is pending a physical. The person spoke Thursday night on condition of anonymity because the deal had not been announced.
The agreement was first reported by Fox Sports.
The 29-year-old Martin hit .211 with 21 homers and 53 RBI in 133 games last year with the New York Yankees. He gives the Pirates needed stability at catcher, where veteran Rod Barajas struggled at the plate and behind it. The Pirates threw out just 12 percent (19 of 154) base stealers last season, the worst percentage in baseball.
The signing reunites Martin with former teammate A.J. Burnett. The two played together with the Yankees in 2011.
Source: Associated Press