The Cubs will send two Double A prospects, pitcher Ivan Pineyro and infielder Elliot Soto to Miami.
Haren, 34, holds a 7-7 record with a 3.42 ERA and 1.09 in 21 starts. The Marlins signed the righthander to a two-year deal in the offseason. He is expected to earn $10.2 million this year.
In 13 major league seasons, Haren, a three-time All-Star, has a 149-129 record with a 3.75 ERA and 1.18 WHIP.
Pineyro, a 23-year-old righthander, has a 3.69 ERA and 1.25 WHIP in 19 starts. Soto, 25, is batting .275 with a .702 OPS.
The Cubs are 54-47 and sit two games out of a wild card berth. Miami, 42-60, is fourth in the National League East.
- Christopher Chavez