He'll face Cubs lefty Jon Lester.
"It's gonna be a fun game against a good team," Freeland said. "At the same time, we got a good team and looking forward to the battle in Chicago."
Freeland (17-7) finished with a 2.85 ERA overall this season. He joined Marvin Freeman (2.80, 1994) and Ubaldo Jimenez (2.88, 2010) as the only Rockies pitchers who qualified for the league ERA title with a mark below 3.00.
Earlier Monday, the Rockies dropped a tiebreaker for the NL West to the Los Angeles Dodgers 5-2. The Rockies-Cubs winner gets Milwaukee in the best-of-five division series starting Thursday at Miller Park.
"Excited about it," Black said. "It's going to be a great environment tomorrow at Wrigley. Their manager and I go way back. This team enjoys playing on the big stage.''
Charlie Blackmon, who had two of Colorado's four hits Monday, called it "an amazing opportunity.''
"The fact of the matter is we have a chance to win the World Series,'' he added.
Colorado and the Cubs split six games this year, each scoring 33 runs. They haven't faced each other since early May.
The Associated Press contributed to this report.