Centre-back Duff and midfielder McCann both sat out last weekend's 1-1 draw against boss Sean Dyche's former club Watford having collected five yellow cards this season.
In their absence, Kevin Long made his first Burnley start at the heart of the defence and the 22-year-old may now revert to the bench.
Fellow defender Ben Mee remains sidelined as he continues his rehabilitation from medial knee ligament damage.
Keith Treacy is pushing for involvement once more after coming on as a late substitute last weekend, the winger's first appearance for the Clarets since August.
Burnley are without a win in their last four matches, having draw three of those games.