Northampton will be without Ben Harding.
Harding was forced off after just seven minutes of the 1-0 win at Dagenham on Tuesday night with an ankle injury and left the ground on crutches.
Town are still waiting to discover the full extent of the problem, but the midfielder will definitely miss out at the weekend.
"Ben's ankle is still very swollen," said manager Aidy Boothroyd. "The swelling has come down a lot but he certainly won't be fit for Saturday. It's too early to tell just how long he is going to be out for but the early signs are good."
Harding and the recovering Seth Nana Ofori-Twumasi (knee) and Shane Higgs (Achilles) will be the only absentees for Northampton, who have right-back Danny East available again after a one-match suspension.
Former Town striker Marc Richards will not be in the Chesterfield squad after he suffered an ankle injury in their midweek win over Accrington.
Marc Richards will miss out on a return to his former club.
Richards, a Cobbler between 2003 and 2005, is set for a spell on the sidelines after suffering an ankle injury in midweek.
The striker, a free summer signing from League Two rivals Port Vale, got his first goal for the Spireites during the 4-3 home win over Accrington on Tuesday night but was carried off on a stretcher late in the game.
He had an X-ray on Thursday and the club are awaiting the results.
Caretaker manager Tommy Wright has limited options as regards a replacement for Richards. Veteran Jack Lester, 36, may be asked to start a third game in eight days or Scott Boden could come in for his first league start of the season.
Wright will hope that midfielder Danny Whitaker can return to the squad after missing the last three matches with a groin injury.