Ipswich boss Roy Keane will be without Jack Colback and Jake Livermore for the visit of the Cobblers.
The on-loan duo are cup-tied having appeared in the competition already for parent clubs Sunderland and Tottenham respectively.
Keane is also still without left-backs Mark Kennedy (hamstring) and Darren O'Dea (knee) with the latter out for around six weeks.
Goalkeeper Marton Fulop recovered from a back injury to face Nottingham Forest at the weekend but Keane is likely to put Brian Murphy or Arran Lee-Barrett in against the League Two side.
Teenage striker Connor Wickham, Tamas Priskin, Troy Brown, Tom Eastman and Ronan Murray could all also some back into the side as Town make changes for the cup tie.
Northampton manager Ian Sampson will have to wait until Tuesday afternoon to discover whether John Johnson is available.
Johnson was sent off in the last minute of the 3-1 defeat at Oxford on Saturday but Sampson has decided to appeal the decision and is hopeful of having him in the side at Portman Road.
Sampson said: "We're going to appeal the decision and I think having looked back at it numerous times on DVD it was a very harsh red card.
"There is minimal contact and the lad has gone down because he hasn't got the ball which has gone into the keeper's hands. He was also going away from goal and having seen some of the decisions made in the Premier League games on Sunday I think it was a very harsh decision to send him off."
Fellow defender Dean Beckwith will miss out as he completes a three-match ban while striker Leon McKenzie will not be involved for the Carling Cup giant killers.
McKenzie has scored four goals in the last two games but is not fit enough to play twice in four days so will be rested for the crunch League Two game with Gillingham on Saturday.