Mellis, a free summer signing from Chelsea, has missed the last seven games due to a severe dead-leg, but could play some part.
Defender Scott Wiseman is not expected to be included despite his proposed move to Blackpool being placed on hold due to the uncertainty over Seasiders manager Michael Appleton's future, while striker Craig Davies this week completed his permanent move to Bolton.
Tykes caretaker boss David Flitcroft, in charge for his third game following the recent sacking of Keith Hill, has no new injury or suspension worries and is expected to keep teenage striker Danny Rose among the substitutes.
Marlon Harewood and Chris Dagnall should continue up front after starting in last week's FA Cup win over Burnley, but Rose could play some part after stepping off the bench to score the Tykes' late winner.
Midfielder Paul Digby, yet to play this season due to persistent trouble with his quad muscles, will again be absent as bottom club Barnsley chase their second win in 15 league matches.