During the past three winter windows, the Blues have been unable to add the necessary players required to deliver League One promotion.
Pompey were sixth on New Year's Day during Jackett’s first season in charge in 2017-18 but would go on to finish eighth.
They sat top at the turn of the year the following campaign but dropped to fourth and suffered play-off semi-final defeat to Sunderland.
And while the Blues moved up from ninth to fifth last term, they again lost in the play-offs to Oxford on penalties.
It total, Kenny Jackett had made 13 signings in the past three January windows.
In truth, the majority of the players recruited haven’t worked out at Fratton Park.
There have been a few who’ve impressed, however, while one signing is very much for the future.
We’ve had a go at ranking those who’ve arrived midway through the season – from worst to best. Scroll down to see our list…
9. 5) Reeco Hackett-Fairchild
It's fairly hard to judge the forward since he arrived from Bromley for an undisclosed fee 12 months ago. Hackett-Fairchild's only played for Pompey once and has spent the first half of the season back on loan at the Ravens. However, he's well regarded by Kenny Jackett and looks one for the future. Photo: Paul Thompson
10. 4) Anton Walkes
The utility man joined Pompey from Tottenham on loan in January 2018. He impressed that season, particularly when playing in a holding-midfield role, which earned him a permanent switch to PO4 in the summer. However, Walkes never quite kicked on afterwards and he left to rejoin MLS side Atlanta last January following one goal in 66 games. Photo: Daniel Chesterton
11. 3) Cameron McGeehan
There was plenty of excitement when the midfielder arrived on loan last January from Barnsley. Although he was steady rather than spectacular, he scored in successive rounds as Pompey booked their return to Wembley in the EFL Trophy. There was a general feeling there was more to come from McGeehan and, despite both parties expressing interest to return on a permanent basis, he inside moved to Belgian side KV Oostende. Photo: Joe Pepler
12. 2) Steve Seddon
Would be some fans' idea of the best January signing under Jackett. Seddon arrived 12 months ago from Birmingham initially as a stop-gap while Lee Brown and Brandon Haunstrup were injured. However, the left-back proved to be revalation with his attacking displays and bagged once in 18 matches. Seddon's been called back by Brum after spending the first half of this season on loan at AFC Wimbledon. Photo: Joe Pepler