Cobblers captain Kelvin Langmead could be ruled out for the rest of the season.
The centre-back underwent knee surgery in the summer and was originally due back in November, but that date was put back to January and now looks like being extended.
“It’s not going to be January for Kelvin,” said manager Aidy Boothroyd. “He’s progressing but it’s going to be longer than we thought.
“We rushed him back last season and everybody was on board with that; Kelvin, myself, the physios, everyone.
“But that has cost him in terms of his time out and it may well be the whole season now.
“He wants to be back as soon as possible and he’s racing to get back in but we’re having to stop him.
“I would say it’s going to be February or March at the absolute earliest for him.”