The most notable departure was Marcus Harness, who moved for an undisclosed fee to rivals Ipswich just weeks before the opening games of the season.
Meanwhile, Aiden O’Brien, Shaun Williams, Callum Johnson, Ollie Webber and Paul Downing all departed for free.
As well as those names, Cowley’s five loan signings also returned to their parent clubs upon the expiration of their deals.
With another turnover of players expected in the upcoming window under John Mousinho, how have last summer’s exits fared since their Fratton Park departure?
Here’s how this season has unfolded for those 12 players.

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From left: Hayden Carter, Gavin Bazunu, Marcus Harness, Paul Downing. Photo: National World

. George Hirst
The striker was tipped with a return to Pompey following his impressive loan stay last term. He spent the first half of the season with Blackburn before Leicester cut his temporary stay short in January and instead sent him out to Ipswich. He’s scored one goal in 10 appearances in all competitions for the Tractor Boys. Photo: Paul Thompson

. Ollie Webber
Webber failed to register a competitive outing for the Blues during his six-month stay where he was second choice to Bazunu. After being released by Pompey, the 22-year-old returned to Northern Ireland, where he penned a 12-month deal with Premiership side Glentoran. Photo: Jason Brown

5. Marcus Harness
The winger was the most notable departure of the summer window as Cowley looked to cash in on his prized asset. Harness joined Ipswich for an undisclosed fee two weeks before the start of the season and has impressed at Portman Road, scoring seven times and registering three assists in 38 appearances to date. Photo: Robin Jones

6. Callum Johnson
The right-back was bombed out of the squad in 2021 and spent his final season at Fratton Park on loan with Fleetwood. He made the switch to Ross County in Scotland after his Pompey departure before making a surprise drop to Mansfield last month. Since his permanent move to the Stags, he’s featured four times in League Two. Photo: Nigel Keene

7. Paul Downing
The centre-back spent the second half of the season on loan at Rochdale before being released by the Blues at the end of his deal. After bringing an end to a difficult three-year-stay at Fratton Park, the 31-year-old is currently a free agent after failing to sign for a new club. Photo: Joe Pepler

8. Gavin Bazunu
After an impressive season with the Blues, the Republic of Ireland completed a £15m move to Southampton upon his return to Manchester City. The 21-year-old has struggled in the Premier League, conceding 41 goals in 24 outings in the top flight. Pompey’s south coast rivals sit at the bottom of the table following their defeat to Leeds at the weekend. Photo: Jason Brown