The White Sox acquired young reliever Tony Pena from the Diamondbacks for well-regarded infield prospect Brandon Allen, the Diamondbacks announced Tuesday night.

The hard-throwing Pena was 5-3 with a 4.24 ERA for Arizona this year. Pena finishes his D-backs' career with a franchise-record 63 holds. He is valuable since he isn't eligible for free agency until after the 2012 season.

Allen, a fifth-round draft selection in 2004, hit .281 with eight home runs and 43 RBIs between Double-A Birmingham and Triple-A Charlotte. He entered the year as the White Sox's sixth best prospect according to Baseball America.

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