Jackson has not started since Aug. 20 because of a strained right lat. He lasted only 2 2/3 innings in his last outing, which was against the Giants, who scored seven runs on eight hits and two walks in the abbreviated start.
Jackson's rehab has involved rest and recovery. He has not faced hitters, but has thrown in the bullpen. The right-hander will have a tough return as he faces the Dodgers and Clayton Kershaw at Wrigley Field.
"It's always fun when you're going against a guy like Kershaw," Jackson said. "It makes the game interesting. You don't think that you're pitching against Kershaw, you're pitching against the Dodgers. You have eight other guys who can swing the bat."
Jackson (6-14, 6.09 ERA) was simply pumped to stop being a cheerleader and get back in a game.
"It feels good to come back," he said. "I've been watching a lot of baseball."
• An MRI revealed Arismendy Alcantara has a mild sprain of his right wrist, suffered when he crashed into the brick wall at Wrigley Field on Monday. Alcantara is day to day.
"He took a few swings today, and he'll be day to day," Cubs manager Rick Renteria said Wednesday.
• Jake Arrieta, who threw a one-hit shutout Tuesday against the Reds, is scheduled for one more start in the final 10 games, Renteria said. The right-hander most likely will start against the Cardinals, who come to Wrigley Field next Monday for a three-game series.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.