Wuertz, 30, split the 2008 campaign between the Cubs and Triple-A Iowa. He was 1-1 with a 3.63 ERA in 45 relief appearances for the Cubs.
A member of the Cubs organization since being selected in the 11th round of the 1997 First-Year Player Draft, Wuertz went 2-3 with a 3.48 ERA in 73 relief appearances in 2007, the second-most outings on the club.
He will compete for a spot in the bullpen among a very crowded field, which includes new acquisitions Luis Vizcaino, Garrett Olson and Dave Stevens.
By signing Wuertz, the Cubs avoided going to arbitration with any of the players who were eligible. The team has not had such a hearing since 1993, when Mark Grace filed for $4.1 million and the Cubs countered with $3.1 million.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.