PITTSBURGH -- The Pirates will open the season with a new starting first baseman after signing free agent Lyle Overbay to a one-year contract. Financial terms of the deal, which was announced by the team on Tuesday, were not immediately known.

Overbay, 33, comes to Pittsburgh after spending the last five seasons with Toronto. The left-handed hitter, who made $24 million over the past four years, batted .243 with 37 doubles, 20 homers and 67 RBIs in 154 games last season. He is a career .274 hitter since breaking into the Majors with Arizona in 2001.

Overbay will get the majority of at-bats at first base, general manager Neal Huntington confirmed. That, in turn, pushes Garrett Jones into a platoon role in right field. Jones will get the bulk of the at-bats against right-handed pitchers, while Matt Diaz will start in right field against left-handers. The Pirates are expected to officially announce signing Diaz to a two-year contract this week.

So what does this mean for Ryan Doumit? He now finds himself pushed into a bench role, where he will back up catcher Chris Snyder and get occasional starts in the outfield. That is, of course, if Doumit remains with the organization.

While the Pirates are not publicly characterizing Doumit as expendable, the club is known to have explored the trade market for the 29-year-old catcher/right fielder. With Overbay and Diaz now in the mix, Doumit could be dealt as a way for the Pirates to address other areas of need.

Huntington was quick to caution, though, that Doumit's $5.1 million salary for 2011 is not a hindrance to the club's payroll flexibility. In other words, he doesn't have to be traded if the Pirates don't find a suitable package.

"Having Ryan Doumit under contract has not impacted our ability to do what we need to this offseason," Huntington said.

If Doumit is with the team next year, it will mark the first time since 2007 that he will open the season without a starting job. Since this time last year, Doumit has gone from being the team's starting catcher to a part-time catcher/right fielder to a bench player.

Doumit hit .251 with 22 doubles and 13 home runs in 124 games for Pittsburgh last season. The Pirates see Jones as a defensive upgrade over Doumit in right, just as they felt Overbay would improve their defense at first.

Overbay's .996 fielding percentage last year ranked second best in the American League. He led all AL first basemen in double plays (150) and assists (101).

The Pirates are intrigued by Overbay's offensive potential, too. He has averaged 17 home runs a season over the last seven years. He was an everyday player during that span and appeared in at least 157 games four times. His best season came in '06, when Overbay hit .312 with 46 doubles, 22 homers and 92 RBIs.

"He's a solid professional on and off the field," Huntington said. "He's a solid Major League hitter. We like the 45-55 extra-base hits a year. His home run power has gone up a little bit at the cost maybe of some batting average. He has solid strike-zone discipline and is a guy that we feel is a good addition to our lineup."

The additions of Overbay and Diaz appear to have addressed the Pirates' concerns on the right side of the infield and outfield. The club is expected to turn its attention now to pitching, where there are still holes in the bullpen and a need to improve the depth in the starting rotation. Upgrading the shortstop position might still be addressed, too.