The Chicago Cubs activated closer Craig Kimbrel from the injured list and returned slugger Anthony Rizzo to the lineup Thursday night for the opener of a crucial four-game series against the NL Central-leading St. Louis Cardinals.

Kimbrel has been out since Sept. 1 due to inflammation in his right elbow. He'll be available Thursday against the Cardinals, who are three games ahead of the Cubs.

The 31-year-old Kimbrel signed a $43 million, three-year contract as a free agent in June. He's converted 13 of 15 save chances, posting a 5.68 ERA in 21 appearances. He also spent time on the IL with right knee inflammation in August.

Rizzo's surprise return was announced 20 minutes before first pitch. He left a game Sunday with a sprained right ankle and was expected to be in a walking boot for up to a week. He warmed up in the outfield prior to Thursday's game, then was inserted into the leadoff spot and tabbed to play first base.

The Cubs also got infielder Addison Russell back Thursday. He cleared concussion protocol and was set to be available off the bench. He missed 10 games after being hit in the head by a fastball.

Left-hander Cole Hamels will miss his next rotation turn because of persistent fatigue in his left shoulder. The veteran hopes to pitch again during a three-game series at Pittsburgh next week.

Righty Alec Mills will start Friday, and lefty Jose Quintana had his scheduled start pushed back a day to Saturday, when Hamels had been scheduled to pitch.

Infielder Javier Baez (fractured left thumb) was cleared for baseball activities and is available to pinch-run with the aid of a protective mitt. The next step would be live batting practice.

Relief pitcher Brandon Kintzler (strained left oblique) reported no setbacks after throwing about 15 pitches Wednesday. The right-hander was expected to take part in a full bullpen session in the next day or two.

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