(CBS) Cubs setup man Pedro Stop has a torn left meniscus that will require surgery and force him to miss four to six weeks, the team said Thursday afternoon.

That timeframe for a return in mid-to-late September means Strop would be available for the postseason should he recover as anticipated. Chicago’s final regular-season game is Oct. 2, and the playoffs start a few days later.

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Strop suffered the injury to his left knee in the eighth inning of Wednesday night’s win against the Angels. His leg bent awkwardly as he fielded a chopper down the third-base line.

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The 31-year-old Strop has a 2.89 ERA and 0.89 WHIP this season in 50 appearances. He’s struck out 56 batters in 43 2/3 innings.

In his place, the Cubs will call up right-handed reliever Justin Grimm.

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In other Cubs bullpen news, fellow setup man Hector Rondon plans to throw a side session Friday and believes he could be ready for game action Saturday or Sunday as he recovers from a triceps injury.