The actor's stepping into the cleats of Oregon Ducks college quarterback Russ Holliday -- and you can see him stretching out before the cameras roll in Atlanta ... featuring him dodging Georgia Bulldogs defenders and charging toward a winning touchdown.

These scenes are all about reliving his character’s glory days, with Glen rocking a youthful mullet, compared to the shaggier look he’s been sporting on other filming days.

The Hulu TV series tracks disgraced football player Holliday’s wild ride -- he dons a prosthetic disguise as 'Chad Powers' to give a flailing Southern football team a much-needed boost and revive his own career.

The role's inspired by Eli Manning’s ESPN+ docuseries "Eli's Places" ... where Eli went undercover in a wig and prosthetic makeup to dive into the walk-on process for college football.