The 29-year-old right-hander was a part of teams that made three straight NL Championship Series appearances and won the World Series in 2016. But he struggled last season with a 1-2 record and 5.53 ERA in 50 appearances.
Grimm had a 3.82 ERA in 4 1/2 years with the Cubs. Chicago acquired him and Carl Edwards Jr. from Texas in a deal that sent Matt Garza to the Rangers in July 2013. Grimm's best season was in 2015, when he had a 1.99 ERA in 62 appearances.
The Cubs announced the move on Thursday.
