Jon Lester will come off DL to start Saturday against Braves

The Cubs have opted for a six-man turn through their rotation.

They’re activating Jon Lester from the disabled list to start Saturday against the Braves.

Lester, who was deemed fit to return from the DL after a 50-pitch bullpen session Wednesday, will make his first start since leaving the mound Aug. 18 in the second inning with lat tightness and shoulder fatigue.

“He’s come out of these different moments well, and he’s smiling, which is always a good sign,” manager Joe Maddon said. “I’m seeing everything trending in the right direction with him.”

Lester’s return won’t bump anybody from the rotation, at least the next time through.

Mike Montgomery, who looked sharp in winning both of his starts in Lester’s place, starts Sunday against the Braves, pushing red-hot Jake Arrieta back one day, into the series opener in Pittsburgh on Monday.

The Cubs are in the midst of 20 games in 20 days.

Montgomery allowed only one run in 13 innings filling in for Lester.

The two-week stretch on the DL ultimately might amount to a breather for Lester, who said he had pitched through the lat tightness for several starts.

He has pitched in the postseason the last four years, including five starts and a relief appearance last fall, when he earned co-MVP honors in the National League Championship Series.

Lester, who hadn’t been on the DL since 2011, was 8-6 with a 3.88 ERA before giving up 16 earned runs in four starts in August (7.85 ERA).

NOTES: Fearing rain in Thursday’s forecast, the Cubs moved up reliever Justin Grimm’s second rehab appearance to Wednesday night for Class AAA Iowa. He pitched an inning, allowed two hits and struck out two.

Grimm (finger) also pitched an inning Monday, allowing a solo home run and striking out two. He’s expected to be activated from the DL this weekend.

• Rookie Ian Happ’s 20th homer, a two-run shot in the third inning, meant the Cubs had a franchise-record six players with at least 20 homers. Five of them are 25 or younger, breaking the major-league record.

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Email: gwittenmyer@suntimes.com