The Houston Astros will be down one of their key players in the World Series, as right-hander Lance McCullers will not be able to face the Atlanta Braves in the Fall Classic due to a lingering strained forearm.

MLB Network's Jon Heyman reported that McCullers hasn't been able to throw since helping the Astros advance past the Chicago White Sox and into their fourth-consecutive American League Championship Series. Houston defeated the Boston Red Sox in six games.

The deadline for finalizing World Series rosters is Tuesday at 11 a.m. ET. Houston had been holding out hope that McCullers could earn a spot and pitch at some point, but he's been officially ruled out, according to Astros reporter Brian McTaggart.

A decision on centerfielder Jake Meyers, who is currently dealing with a shoulder injury, has not been made.

McCullers has not pitched since the Divisional Round. He won two games vs. the White Sox before suffering the injury in Game 4.

The veteran righty co-led the Astros with 15 wins in 2021 (tied with ace Zach Greinke) and led his team with 185 strikeouts. His 3.16 ERA was second to Greinke.

Dusty Baker will hand the ball to 27-year old left-hander Framber Valdez for Game 1. He'll start against Atlanta's Charlie Morton — who pitched for the Astros in 2017 and 2018 and helped Houston win the World Series in 2017.

Valdez gave up one run in eight strong innings in his last start, in Game 5 of the ALCS.

The Fall Classic begins on Tuesday night.