A number will have benefitted Pompey financially, with offers for the likes of Matt Clarke, Marcus Harness and Jamal Lowe too good to turn down.
Others, though, will have raised a few eyebrows and left many supporters disappointed.
Indeed, there’s quite a few departures that make you wonder ‘what if?’ if more of an effort had been made to retain certain individuals.
Here are 18 former Pompey players we believe fit into that latter category since the Blues returned to League One in 2017.
13. Tom Naylor
The Blues captain departed Fratton Park in the summer of 2021 in favour of a move to Wigan on a free transfer. Naylor was offered a new contract to remain on the south coast – but on reduced terms. Photo: Joe Pepler
14. Ben Thompson
The on-loan Millwall midfielder endeared himself with the Fratton faithful during 27 appearances over the first half of the 2018-19 season. He was recalled early to the Den in January 2019 - and with his departure went Pompey's promotion hopes. Hopes of a permanent return remained for several years, yet nothing ever materialised. Photo: Joe Pepler
15. Steve Seddon
The on-loan Birmingham left-back made an instant impression during his 2019-20 spell at the Blues. The ex-Reading man scored one goal in 18 appearances, with his marauding performances down the flank making him a real fans' favourite. He returned to St Andrews at the end of that season but was linked with a Pompey reunion in January 2021.However, Brum's wish for a permanent move scuppered a second loan return. Photo: Robin Jones
16. Cam Pring
The defender was recalled by Bristol City in January 2021, cutting short a scheduled season-long stay at Fratton Park. The Championship side acted after first-choice left-back Jay Dasilva was sidelined by a stress fracture of the shin. As a consequence, they activated a January recall clause in Pring’s Pompey arrangement. Former Blues chief executive Catlin told The News at the time: ‘Cam has gone back and it’s unfortunate. It was purely from the Bristol City side, we would have loved to have kept Cam until the end of the season.' Photo: Joe Pepler