Winger Sergio Torres could be the man to make way with George Boyd moving back to his usual wide role after three games alongside Aaron Mclean in attack.
Ferguson's only problems remain Wales international Craig Morgan, who is sidelined with a toe injury, and midfielder Lee Frecklington who is still three weeks away from a return from his hamstring tear.
Posh will be looking for a first home win against the Cobblers since 2001 to keep the pressure on MK Dons and Leicester at the top of the table.
Northampton manager Stuart Gray could hand starts to Liam Davis and Iketchi Anya.
The duo came off the bench during the 1-0 defeat at Millwall in midweek and impressed, so could be unleashed from the start at London Road. Davis has recovered from a hernia operation and topped up his fitness in a reserve-team draw with Posh on Wednesday.
Midfielder Ryan Gilligan will have surgery on his knee injury on Friday and will miss out.
Luke Guttridge is back in the side after a knee problem but Gray will again be without top scorer Adebayo Akinfenwa.
Akinfenwa must serve the fourth and final game of his suspension for his sending off at Brighton, so former Peterborough striker Leon Constantine will continue to lead the line.
Sporting Life