(CBS) The Cubs are set to welcome back their ace this weekend.

Left-hander Jon Lester on Wednesday was cleared to rejoin the Cubs’ rotation and will make a start Saturday against the Braves at Wrigley Field. Lester has been sidelined since Aug. 17 with left shoulder fatigue and lat tightness.

Mike Montgomery will make a start on Sunday, with the Cubs pushing back Jake Arrieta to Monday. No decision has been made on whether Montgomery will remain in the rotation or return to the bullpen.

Lester is 8-7 with a 4.37 ERA this season. The Cubs moved to 72-60 on the season Wednesday night with a 17-3 win over the Pirates.

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