The Cobblers will send goalkeeper Jordan Archer back to Tottenham Hotspur in January and use Matt Duke as their first-choice stopper for the remainder of the season.
Duke deputised for the on-loan Spurs man when he was suspended in the defeat to Plymouth Argyle at Sixfields eight days ago.
And it was the 37-year-old who was again on glove duty at Carlisle United on Saturday, with Dean Snedker - who has been recalled from his loan at Brackley Town - on the bench and Archer not travelling.
The plan will now be to use Duke for the remainder of the season and reallocate the budget spent on Archer elsewhere.
“We’ve made the decision to go with Dukey for the rest of the season,” confirmed manager Chris Wilder. “We feel that you work with a budget and it’s not a problem for us to have him in goal.
“We’d like competition in every area but I might have to put a bit of money somewhere else and I don’t see it as an issue to have Matt in goal.
“Matt has done well when he has played.”
One other player who was a surprise omission from Saturday’s squad is Emile Sinclair, who remained at Sixfields with a hamstring injury.
Wilder is growing increasingly frustrated with the striker’s fitness issues, and said: “It’s ridiculous with Emile, he’s not got himself going.
“He’s got a problem with his hamstring and he hasn’t trained since after the Plymouth game.
“That’s not good for me, a player that we brought in to play can’t seem to get himself fit and on the pitch for me to select him.”