A Gold Glove winner in 2001 with the Minnesota Twins, the 32-year-old Mientkiewicz hit .283 with four homers and 43 RBI last season for the Kansas City Royals before season-ending back surgery in late August.
"There's not too many first basemen who could save two, three runs a game," Yankees center fielder Johnny Damon, his former teammate in Boston, said last month. "Defensively, I haven't seen a better defensive player than Doug, so if we pick him up, it would be great."
A left-handed hitter, Mientkiewicz would see time at first along with Jason Giambi, who figures to get increased time at designated hitter this year.
In 2004, Mientkiewicz caught the throw from reliever Keith Foulke for the final out of the first World Series title for the Boston Red Sox since 1918. Mientkiewicz at first kept the ball, then loaned it to the Red Sox and eventually gave it to the Hall of Fame.
Mientkiewicz's decision to sign with the Yankees first was reported by the New York Post and Daily News.
It remains unclear whether the Yankees will have room for Bernie Williams, who saw time in the outfield and DH last year. Damon, Hideki Matsui and Bobby Abreu have the three starting spots in the outfield, and Melky Cabrera is the backup. However, the Yankees have discussed possible trades involving Cabrera.