The hard-throwing, right-handed relief pitcher was placed on the 15-day injured list during Houston's stretch run into the postseason, the club announced Tuesday.
The Astros announced Stanek suffered a right ankle sprain when he tried to cover first base during his ninth-inning appearance Monday against the Texas Rangers.
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Left-handed pitcher Parker Mushinski was recalled to take the spot left open by Stanek, who enters this offseason as a free agent.
Stanek, 32, appeared frustrated when he was placed on a motorized cart after his injury.
The former first-round pick in the 2013 MLB Amateur Draft appeared in 53 games this season, with a 4.07 earned run average over 48 and two-thirds innings pitched.
Stanek came over to the Astros as a free agent before the 2021 season, and he remained with Houston on a one-year deal ahead of 2023.
With word of the sprain, the 'Stros avoided the worst-case scenario with 23 games left in the regular season. The pitching staff has been battered with key injuries, most notably to starting arms Luis Garcia and Lance McCullers Jr., who were lost for the season.
Heading into their game Tuesday night against Texas, the Astros are tied with Seattle atop the American League West division and are a game up on the Rangers.
The first pitch in Arlington is set for 7:05 p.m. Framber Valdez is the starting pitcher against Alvin native, Nathan Eovaldi.
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