Town have been going along nicely in the last few weeks and currently sit second in Sky Bet League Two, but they remain reliant on a core group of 13 or 14 first-team players, with those on the fringes struggling to make an impression.
A strong transfer window could therefore be the difference between finishing the job with promotion or just missing out, and Cobblers will go into January without head of recruitment Martin Foyle, who recently departed for Morecambe.
That has led to a reshuffle behind the scenes with the well-connected Calderwood now taking on more responsibility for the club's recruitment strategy.
"I think we will be looking to fill around the edges a little bit," Calderwood told the Cobblers Show on BBC Radio Northampton when asked about January. "We do have our specified targets but I won't be giving anything away!
"What you have to remember is that the boys who are starting at the moment are doing pretty well so we need to be shrewd and understand that not everyone will come here and play.
"We don't want to add a number to our squad who won't have any influence between now and the end of the season, but we are aware that we need a little bit more strength in depth in certain areas.
"We're not looking at wholesale changes, we know exactly what we want and we have good information on the players that might be available.
"A bit more variation might help as well. Do you keep doing what you're doing or do you take something that's completely different to what we've got? Will that add to us or take something away from the ethos of the group?
"But we also know that the group have to improve and the players know that and they feel there's improvement in them. The great thing about Jon and Marc (Richards) is that they're teachers and coaches and they want to help players improve and develop.
"At the minute everyone is smiling and happy because we're on a good run but the real test is when you lose. We rebounded earlier in the season but it will happen again and we will have to cope with having a bit more spotlight on us."