Seventeen-goal striker Akinfenwa was substituted at half-time against Bristol Rovers on Tuesday night following a heavy fall on his hip.
Hackett was not in the squad for the 1-0 home win, with manager Aidy Boothroyd resting him to ensure his freshness for the weekend game against the Grecians.
Both were excused from full training on Thursday but will train with the squad on Friday ahead of the journey to the south west.
Joe Widdowson is also available again after serving a two-match suspension and he could line up on the left side of midfield - as he did at Southend and Wimbledon recently - with Lee Collins performing well at left-back.
Boothroyd said: "Two or three months ago I'd have said we can't leave Joe out of the team, but Lee has been rock solid and so there is a decision to make there."
One player who will not be travelling is Manny Oyeleke, who has returned to Brentford following the completion of his loan spell.
The 20-year-old midfielder made just two appearances for the Cobblers, starting the defeat at Rotherham and coming on as a substitute in the win at Southend.