One of the most sparse positions on baseball's free agent market just became even thinner, much to the delight of the White Sox.

The Sox signed infielder Jeff Keppinger to a three-year, $12-million contract Monday to address their No. 1 need – a third baseman. Keppinger will make $3.5 million in 2013, $4 million in 2014 and $4.5 million in 2015.

Keppinger is penciled in as the Sox’s Opening Day third baseman, and his versatility affords general manager Rick Hahn to stay active in free agency while giving manager Robin Ventura flexibility with his lineup. Keppinger said he hadn’t discussed where he would play with the Sox but that it doesn’t matter given his history of playing different positions during his career. He’s capable of playing any infield position and should push second baseman Gordon Beckham, who has yet to reach his potential.