Langford has returned to Australia but will be back to Limerick in late December while Wallace is still recovering from a shoulder injury.
Killian Keane, who captained the Irish Development side last Sunday, is available as is Paul Neville while there is optimism in the club that Dominic Crotty's hand injury may have progressed sufficently to allow him play.
Garryowen's latest senior international cap, Jeremy Staunton, is unlikely to feature while his brother John (shoulder), along with Colin Varley (groin) and Shane McCarthy (hand injury), will undergo fitness testing to determine their availability. All three are receiving medical attention, and will be assessed
Garryowen, unbeaten in three league outings so far, lie fifth in the table on ten points, two places ahead of Dungannon.
AIB League Division One. Garryowen v Dungannon. Ballymena v Cork Constitution. Blackrock College v Young Munster.
AIB League Division Two. Old Crescent v Belfast Harlequins. Sunday's Well v Ballynahinch.