Grabow posted a 3.24 ERA with the Cubs, who acquired him July 30 from Pittsburgh along with lefty Tom Gorzelanny for Kevin Hart, Jose Ascanio and Josh Harrison.
For the season, Grabow set a career mark with 75 relief appearances, pitching in 45 games with the Pirates and 30 with the Cubs. Grabow, who turned 31 on Nov. 4, began his stint in Chicago with 16 consecutive scoreless appearances.
Monday marked the 12th day of a 15-day period in which eligible players may file for free agency. So far, 168 players have filed. Rich Harden, Reed Johnson, Kevin Gregg and Chad Fox have already filed.
Gregg and Grabow were classified as Type A free agents, which means if another team were to sign them, the Cubs would receive a first-round pick as compensation. Harden was classified as a Type B free agent, and the Cubs would receive a sandwich pick between the first and second rounds. The Cubs only receive compensation if the player signs elsewhere before Dec. 1 or is offered arbitration and declines.
The Cubs have had discussions with Grabow's agent, Paul Kinzer, about a possible two-year contract. Grawbow made it clear at season's end that he'd like to return.
"I want to come back," Grabow said in October. "[Cubs general manager Jim Hendry] knows that. It's just a matter of getting it done."
Grabow is one of the top lefty relievers available on the free-agent market, joining Joe Beimel, 32, who had a 3.58 ERA in 71 games with Washington and Colorado, and Darren Oliver, 39, who had a 2.71 ERA in 63 games with the Angels.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.