Volstad, 26, was acquired by the Royals via waivers from the Chicago Cubs on Oct. 26. In 2012, he pitched to a 3-12 record with a 6.31 ERA while striking out less than five batters per nine innings. This was a far cry from Volstad's debut season as a 21-year-old in 2008, in which he finished with a 2.88 ERA.
Pena, 30, spent four seasons with the Royals, posting a .251/.291/.355 batting line. His best season came in 2009, when he put up a .761 OPS in 183 plate appearances, while hitting six home runs. Pena made his big league debut in 2005 as a 23-year-old with the Atlanta Braves, hitting .179 in 18 games. A part-time player with less than 1,000 career plate appearances, Pena is a .248 lifetime hitter.