Lamb will report to extended spring training in Port St. Lucie, Fla., before he is assigned to Triple-A Buffalo. He was released by Milwaukee on April 1 after hitting .250 with two homers and 12 RBIs this spring.
The Mets also re-signed right-hander Nelson Figueroa to a minor league deal and assigned him to Buffalo. Figueroa was designated for assignment on Sunday after being called up from the minors to make a spot start for the Mets against Milwaukee.
The 33-year-old Lamb spent last season with Minnesota and Milwaukee, batting .235 with one homer and 32 RBIs. He played in 92 games, 81 with the Twins.
Lamb is a .277 career hitter with 69 home runs and 345 RBIs in nine major league seasons. He has seen most of his action at third base and first base, but pitcher, center field and shortstop are the only positions he hasn't played.