Cubs shortstop Addison Russell was called back to Chicago to be examined after experiencing a setback in his recovery from a right foot injury.
Russell was scratched from a rehab game with Triple-A Iowa on Wednesday after experiencing soreness. The 2016 All-Star has been sidelined since early August after straining the foot.
"Tough one," manager Joe Maddon said. "You look at the shortstop position. Of course, Javy (Javier Baez) is doing a wonderful job. But after that, it becomes different. We were counting on this to happen, Addy to get back quickly. Hopefully, it's not going to be anything prolonged. That's such an important position."
The news on ace Jon Lester (left lat tightness and shoulder fatigue) was more encouraging. He is scheduled to pitch Saturday against Atlanta after his 50-pitch bullpen session Wednesday went well.