The Cubs announced they have formally signed Villanueva to a two-year, $10 million deal on Saturday. Right-hander Lendy Castillo, acquired in the Rule 5 Draft in 2011, was designated for assignment to make room on the 40-man roster.
The 29-year-old Villanueva has experience both in the rotation and the bullpen, having started 56 of his 301 career games over seven big league seasons. Over the past two years with the Blue Jays, the Dominican Republic native has made 29 starts and 42 relief appearances.
Villanueva went 7-7 with a 4.16 ERA overall in 2012. He was 5-7 with a 4.50 ERA and a 3.44 strikeouts per walk ratio as a starter, and 2-0 with a 3.24 ERA and 1.71 K/BB out of the bullpen.
The Cubs also have signed right-handers Edwin Jackson, Scott Baker and Scott Feldman this offseason, to go along with Villanueva and returning lefty Travis Wood. Matt Garza and Jeff Samardzija are back at the top of the rotation.
Villanueva made his debut for the Brewers in 2006 and pitched for Milwaukee through 2010. He owns a career 33-35 record, with a 4.26 ERA and marks of 7.8 strikeouts and 3.1 walks per nine innings.
Castillo went 0-1 with a 7.88 ERA over 13 relief outings for the Cubs last season. The 23-year-old spent the previous five years in the Phillies' organization.
Andrew Simon is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.