The Chicago Cubs have officially activated left-handed pitcher Mike Montgomery from the 10-day disabled list. 

Montgomery, who has a 4-3 record and a 3.08 ERA this season, will make the start for the Cubs when they take on the Atlanta Braves in a make-up contest at SunTrust Park. 

Pitcher Alec Mills has been optioned to Triple-A Iowa to make room for Montgomery on the roster, the team announced. 

Montgomery had been dealing with shoulder inflammation in his left arm, but only required a 13-day stay on the disabled list with the ailment. 

First pitch between the Braves and Cubs is set for 6:35 p.m.