Plumtree will act as cover for Wainwright and Taulupe Faletau, who is the other specialist number eight in the initial squad but missed the game at Stade de France because of a knee injury.
Wainwright was replaced by Leicester flanker Tommy Reffell during Friday’s match, with James Botham switching to number eight during the game.
Plumtree was left out of the squad initially after featuring in the autumn series where he packed down at number eight against South Africa.
No centre cover has been drafted in with Wales still able to call on the likes of Nick Tompkins, Ben Thomas, Eddie James and Joe Roberts.
This means there remains no call-up for Gloucester centre Max Llewellyn or his club team-mate fly-half Gareth Anscombe.
Wales face Italy on Saturday with Gatland’s side bidding to avoid a 14th consecutive international defeat.
