Preston captain John Welsh is doubtful for the visit of fellow high-fliers Rotherham to Deepdale.
The central midfielder missed the 2-1 win at Colchester on Saturday because of a knee injury and although he attended training on Monday, it is uncertain if he can make a swift recovery in time.
Full-back Scott Wiseman has a better chance of featuring, though, with his problem considered less serious after he took full part in Monday's training session.
Boss Simon Grayson and his men can cut the gap on the three sides above them, none of whom are playing on Tuesday night.
Rotherham striker Alex Revell is a major doubt for Tuesday's crunch clash at Preston.
The striker suffered a cut above his eye during Saturday's win at Carlisle boss Steve Evans says he "looks like he's been in a boxing match".
But the Millers could be boosted by the return of former North End defender Craig Morgan (tonsillitis) and Mark Bradley (back), though Rob Milsom (back) is not expected to be fit despite a return to full training.
Rotherham travel to Deepdale three points behind their hosts, but they have won six of their last seven games knowing a win tonight would see them leapfrong North End into fourth spot.
Source PA