The full back limped out of last weekend’s 1-0 win over Sheffield United inside half an hour with a hip problem picked up in an early challenge.
Kevin O’Connor came on in the former Rotherham man’s place as Alex Neil’s side picked up a third straight win and extended their unbeaten Championship run to six games.
Fisher could return to training later this week but it looks like the final game before Christmas could come too soon for a man who has quickly established himself as a key figure since his summer move to Deepdale.
“It’s not going to be long-term, he’s just jarred his hip,” said PNE boss Neil.
“We’re hopeful that he could potentially do some work with us on Friday but he looks doubtful now.”
The 23-year-old’s injury is another reminder that while the worst of PNE’s crisis at the back is over it is still far from clearing completely.
Left back, where Fisher has started the last two games, has been something of a problem position with Greg Cunningham, Josh Earl and Calum Woods all still on the sidelines.
“We’ve come out of the other side of it but we’re still not there with the injuries,” said Neil.
“Tom Clarke is playing right back the moment and it looks like he’ll be the only one available at the weekend because Darnell is probably going to be missing.
“We’ve got four left backs missing in total.”
O’Connor could be handed a third league start since his summer move from Cork City having come off the bench in the last three games.
Ben Davies played the first 45 minutes of the win over QPR at left back but was shifted inside at the interval having impressed at the heart of the defence this season alongside long-time stand-in captain Paul Huntington.