The past two seasons were spent in Chicago, where Villanueva was 5-7 with a 4.64 ERA in 42 games, including five starts, during 2014. Over 77 2/3 innings, he allowed 89 hits and 19 walks with 72 strikeouts.
Villanueva was more effective as a reliever, with a 2.64 ERA and .226 opponents batting average compared to a 1-4 record and 10.53 ERA as a starter while opponents batted .404.
St. Louis has a starting staff that already includes Adam Wainwright, Lance Lynn, Michael Wacha, John Lackey, Carlos Martinez and Marco Gonzales, with Jaime Garcia coming off an injury-shortened season. Villanueva could be a long shot to start in 2015, but he could bring added depth for the rotation while working from the bullpen.
Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. This story was not subject to the approval of Major League Baseball or its clubs.