Cubs to use 6-man rotation; Addison Russell to have foot examined

CHICAGO -- The Cubs got some good and bad news on the injury front, as they plan to activate lefty Jon Lester (shoulder) from the disabled list in time to start Saturday's game against the Atlanta Braves but shortstop Addison Russell experienced a setback in his recovery from a foot injury.

"They have to re-evaluate it and look at it more closely," manager Joe Maddon said after the Cubs 17-3 win over the Pittsburgh Pirates on Wednesday. "Obviously there was something that was sorer. It's a tough one."

Russell hasn't played since Aug. 2 with a severe case of plantar fasciitis in his right foot, but he was preparing to return to the Cubs after a short rehab stint at Triple-A Iowa. He was scheduled to play his second game with Iowa on Wednesday night but instead was scratched and told to fly back to Chicago to get examined by doctors on Thursday. The Cubs are very thin at shortstop behind current starter Javier Baez.

"You look at the shortstop position and Javy is doing a wonderful job but after that it becomes different, so we were counting on this to happen," Maddon said. "Addy [Russell] getting back quickly, hopefully it's not anything prolonged. That's such an important position. Just imagine without either one of them out there. Very difficult to imagine."

The first-place Cubs could add from outside the organization, but if they want a player eligible for the postseason roster they need to acquire him by midnight on Friday.

Meanwhile, Lester threw a bullpen session on Wednesday afternoon and the Cubs declared him ready to return. They plan on using a six-man rotation partly because Lester's replacement, Mike Montgomery, gave up just one run in 13 innings over two starts. It means the rest of the staff will get an extra day of rest during a stretch of 20 games in 20 days. Jake Arrieta will start on Monday with Montgomery getting the ball the day after Lester.