Pena became a stalwart out of the Revolution bullpen during the second half of the 2015 season, holding a 2.75 ERA with a 2-2 record and one save in 36 appearances, while limiting opponents to just 34 hits and eight walks compared to 31 strikeouts in 39.1 innings.  The big league veteran finished with scoreless outings in 26 of his final 28 appearances.  The 34-year-old has 313 Major League appearances between 2006 and 2011 with the Diamondbacks and the White Sox, and appeared in a career-high 75 and 72 games for Arizona in 2007 and 2008, respectively.  In 2010 with Chicago, Pena filled more of a long role, throwing a MLB career-high 100.2 innings in 52 appearances, which included the only three big league starts of his career.  Pena also owns eight saves at the big league level, and ranks second in Diamondbacks history in holds with 55 as a late-inning reliever.  Last season, Pena saved 27 games for Laguna of the Mexican League before joining York.  The Dominican Republic native made the rare professional debut at the Double-A level in 2004 at age 22, a short journey to his Major League debut just two seasons later.  He was first signed as an international free agent by the Diamondbacks in 2002.