The Cubs also announced Sunday they had signed Tim Collins to a one-year deal, and then optioned the left-hander to Triple-A Iowa. Collins had no record and a 4.37 ERA in 38 appearances with Washington last season.
Duensing signed a $2 million, one-year contract with Chicago before the 2017 season, and then went 1-1 with a 2.74 ERA in 68 appearances. The lefty finalized a $7 million, two-year deal with the Cubs in January 2018, but he struggled last season, going 3-0 with a 7.65 ERA in 48 games.
The 36-year-old Duensing is 46-38 with a 4.19 ERA in 10 years in the majors, also playing for Minnesota and Baltimore.
Collins, 29, is 12-17 with a 3.62 ERA in 266 relief appearances with Kansas City and Washington.
The Cubs open the season on Thursday at Texas.