The Hawks announced the deal on their website on Friday. The Pacific League club won the 2011 championship, defeating the Central League's Chunichi Dragons in seven games. It was the club's first title in eight years.
Pena, who will turn 30 in January, played eight seasons in the Majors with the Reds, Red Sox, Nationals, D-backs and the Mariners.
The right-handed hitter started the 2011 campaign with the D-backs, hitting five home runs in 22 games before being released on July 15. He inked a Minor League deal with the Mariners on Aug. 13, and played 22 games with Seattle. He totaled 23 hits in 113 at-bats for the season.
The Dominican Republic native was originally signed as an amateur free agent by the Mets in 1998, then inked a deal with the Yankees a year later after his contract was voided. In March 2001 he was traded to the Reds for Michael Coleman and Drew Henson. He made his Major League debut in 2002 with the Reds.
Pena won a World Series ring for contributing to the 2007 Red Sox, who traded him to the Nationals during August of that season. He compiled 425 hits, 84 home runs and 240 RBIs during his eight-year career.
Matt Weber is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.