Youga was also red carded after two quickfire bookings at the Ricoh Arena, so must sit out.
On-loan Manchester City youngster Shaleum Logan is expected to revert to right-back at Home Park, having been deployed on the wing in midweek.
Midfielder Matty Sparrow could return to contention after a hamstring problem kept him out on Tuesday.
Defender Izzy Iriekpen is available again after serving a three-match ban for violent conduct in a reserve match against Grimsby, but has a back problem.
Winger Kevan Hurst suffered a knock at Coventry, but is expected to recover in time to play.
Plymouth manager Paul Sturrock will be in charge for the first time, after watching the midweek game against West Brom from the directors' box.
He will be without on-loan Manchester united winger Lee Martin, as he has a hamstring problem.
Teenager Dan Gosling took his place in midweek, but he was replaced by Jimmy Abdou at half-time, with both hoping to start.