Mumford amassed 35 hitouts and finished with nine disposals, but also gave away five free kicks as the Bombers’ ruck combination of Tom Bellchambers, Shaun McKernan and Cale Hooker ran him around Marvel Stadium.
“He is shot,” Wallace told SEN Afternoons on Friday.
“He can’t get around the ground, he’s got no lateral movement – he is gone.
“He got absolutely slaughtered over in Adelaide at Adelaide Oval, (Melbourne’s) Max Gawn absolutely took him to the cleaners and from what I saw last night (against Essendon), five free kicks in the first 40 minutes.”
Wallace believes Mumford should have a rest between now and the finals, or even look at another option to replace the 32-year-old, who came out of retirement to add depth to GWS’ ruck stocks last November.
“Either he’s got to have a bit of a rest and freshen himself up to be able to get through at some sort of level, or they’ve got to look what their alternatives are,” Wallace said.