CHICAGO -- The White Sox and left-handed reliever Will Ohman have agreed to a two-year, $4 million deal, the club announced Monday.

Ohman, who will receive $1.5 million in 2011 and $2.5 million in '12, fills the need of a left-hander sought out by the White Sox to complete their bullpen changeover, possibly being used in a situational role or in the middle innings. That 2011 changeover includes the addition of fellow free agent Jesse Crain and the departure of Bobby Jenks, Scott Linebrink and J.J. Putz.

The addition of Ohman, 33, sets up White Sox relievers extremely well against a team with significant left-handed punch, such as the defending American League Central champion Twins, featuring Joe Mauer, Justin Morneau and Jason Kubel, with Ohman joining fellow southpaws Matt Thornton and Chris Sale.

But general manager Ken Williams told MLB.com in September that Sale would prepare as a starter during Spring Training and could temporarily take Jake Peavy's spot in the rotation while the right-hander works his way back from a season-ending detached latissimus dorsi in his right posterior shoulder.

Although White Sox pitching coach Don Cooper prefers to have Sale stick with one job and not spend only one month in the rotation, Sale still will be stretched out as a starter in Arizona. With Ohman being added, the club also has the flexibility to move one of its starters via a trade to open up a spot for Sale and also free up money to possibly pursue free-agent closer Rafael Soriano.

During eight seasons covering stops with five teams, Ohman has produced a 4.09 ERA with 269 strikeouts over 273 innings. He split the 2010 campaign between the Orioles and Marlins, posting a 3.21 ERA over 68 games. The most important career statistics for Ohman stand as his .208 batting average against and 1.20 WHIP when facing left-handed hitters. Ohman also has an understanding of pitching in Chicago, having worked his first five seasons for the Cubs.