New signing Giles Coke is facing the possibility of a further operation.
The summer signing from Mansfield has suffered a flare-up of the knee ligament injury that has sidelined him since January.
It was thought the midfielder would be involved in first-team training by this stage but instead he was visiting a specialist today to establish the extent of the problem.
The most likely scenario is that a further operation will ne required for the 21-year-old.
Meanwhile, Danny Jackman remains the only absentee for the Cobblers ahead of their trip to Middlesbrough in the Carling Cup. He has been sidelined with a knee injury.