Peltier missed the weekend win over Sheffield Wednesday due to a sprained ankle, while fellow defender Lees sat out the final game of a three-match suspension.
Stephen Warnock switched to the heart of defence on Saturday, with Adam Drury recalled to the starting line-up, but McDermott may be tempted to make further changes in his second game in charge.
Midfielder Michael Brown serves the second game of his two-match ban, but McDermott has no other new injury or suspension worries.
The former Reading manager employed Luke Varney in a central striker's role against Wednesday and was rewarded with a two-goal haul from the former Crewe, Charlton and Derby forward so could opt to keep him alongside Ross McCormack.
El-Hadji Diouf made a big impression as a second-half substitute at the weekend and is pushing for a recall as Leeds bid to take a final step towards safety.