Etuhu, operating in midfield under Flitcroft, picked up a knock in Saturday's goalless draw at Crystal Palace and was replaced just after the hour-mark by winger Jim O'Brien.
Flitcroft, who has no other new injury or suspension worries, could be boosted by the return of defender Martin Cranie (hamstring), who failed a late fitness test ahead of the Palace game.
Stephen Foster was recalled to the Tykes' defence on Saturday and will continue if Cranie fails to make it.
Striker Reuben Noble-Lazarus, defender Jimmy McNulty (both ankle), and Rory Delap (calf) remain sidelined, while left-back Scott Golbourne is out until pre-season due to a knee injury.
The Tykes, who have lost only one of their last five matches, are bidding to extend the one-point gap between themselves and the bottom three.