Overbay, 34 next month, hit 20 home runs and 37 doubles last year with the Blue Jays. He batted .243 with 67 RBIs, the second fewest among all major league starting first basemen with at least 475 at-bats at the position.
The Pirates, again restricting their free agent activity to budget-priced players, plan to start Overbay at first. Garrett Jones and the recently acquired Matt Diaz are expected to platoon in right field. Jones hit .247 with 21 homers and 86 RBIs last season as Pittsburgh's primary first baseman.
"Lyle Overbay is a solid major league player and we expect him to have a positive impact on our club offensively, defensively and in the clubhouse," Pirates general manager Neal Huntington said.
Pittsburgh has had 18 straight losing seasons and its 57-105 record was its worst in 58 years.
The additions of Overbay and Diaz likely will allow the Pirates to trade Ryan Doumit, who is primarily a catcher but has also played the outfield. He is due $5.1 million in 2011.
Neither Diaz (Braves) nor Overbay (Blue Jays) were tendered contracts by their former clubs, thus allowing them to become free agents. Overbay made $7.95 million last season, the final year of a $24 million, four-year contract. Diaz signed with the Pirates for $4.25 million over two seasons.
Overbay should upgrade what was the majors' worst defense last season. He led the AL in double plays and assists by a first baseman.
Overbay's best season at the plate came in 2006 with Toronto when he hit 20 home runs and 46 doubles with 92 RBIs.
He made his major league debut with Arizona in 2001, was traded to Milwaukee before the 2004 season and dealt to Toronto before the 2006 season. In parts of 10 years, he is a .274 hitter with 122 home runs and 524 RBIs.