After suffering a 2-1 loss at Doncaster on Tuesday, the boss needs to find a way of remedying the Blues’ faltering League One promotion bid.
A top-two finish is looking more and more unlikely, with Pompey now facing a battle to cement a play-off spot.
Jackett's side not only need to deliver three points against the relegation-threatened Cobblers but deliver a performance that can prove the fillip for a big push in the business end of the season.
The Pompey manager will surely make changes from the loss to Donny, with teenager Haji Mnoga likely to be taken out of the side.
The Blues are hopeful James Bolton will be back fit while Michael Jacobs is also back in training.
Here’s how we think the visitors will line-up at Sixfields...
9. Right-forward
The Aussie hasn't started the past two games but must surely be in contention. Photo: Joe Pepler
10. Striker - John Marquis
Scored a decent goal at Doncaster and having George Byers in midfield will surely create more chances for Pompey's top scorer. Photo: Joe Pepler
11. Left-forward - Ronan Curtis
Michael Jacobs likely won't be fit to start so Ronan Curtis should keep his starting spot. After playing as a striker in the past three games, he might be moved to his recognised role on the flank. Photo: Joe Pepler
12. Sub 1 - Lewis Ward
Will remain Pompey's No2 for some time with Alex Bass absent for six weeks. Photo: Joe Pepler