Chicago traded Drew Smyly to the Texas Rangers, Hamels's former team.
The Chicago Cubs picked up starter Cole Hamels's $20 million option, the club announced Friday.
Chicago also traded lefty Drew Smyly and a player to be named later to the Texas Rangers in exchange for a player to be named later.
The Cubs had until Friday's 4 p.m. ET deadline to decide on Hamels's 2019 option. If Chicago declined, the Rangers, Hamels's former team, would have paid a $6 million buyout, allowing him to become a free agent.
Hamels, 32, recorded a 2.36 ERA in 12 starts after being acquired by the Cubs on July 27.
By trading Smyly, the Cubs will cut $7 million from their payroll. Smyly signed a two-year, $10 million deal with the Cubs last offseason while he was recovering from Tommy John surgery but did not play during 2018.