Corpas, 29, is 12-16 with 34 saves, 51 holds and a 3.93 ERA in all or part of five Major League seasons with the Rockies. He underwent Tommy John surgery in September 2010 and missed all of last season. He has struck out 206 and walked 80 over 286 innings, an average of 2.5 walks per nine innings.
He became Colorado's closer midway through 2007 and helped the team get to the World Series, going 4-2 with 19 saves and a 2.08 ERA in 78 appearances.
Sonnanstine, who turns 29 in March, has pitched all or part of the last five seasons with the Rays and has been utilized as both a starter (80 starts) and a reliever (52 outings). He began his career by making 71 straight starts before pitching primarily in relief the last two seasons. Overall, he is 28-31 with one save and a 5.26 ERA in his career, walking 136 in 540 1/3 innings, an average of 2.3 walks per nine innings.
He reached the Majors with the Rays in 2007 and was 13-9 with a 4.38 ERA in 32 starts to help them win the '08 American League Championship. During that season, Sonnanstine issued 37 walks in 193 1/3 innings, an average of 1.7 walks per nine innings.
The right-hander split the 2011 season between Tampa Bay and Triple-A Durham. He was 0-2 with a 5.55 ERA in 15 big league appearances (four starts) and went 3-6 with a 4.82 ERA in 10 Minor League outings, all but one as a starter.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter@CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.