Pompey have been plagued with injuries across the back-line this season with captain Clark Robertson and Paul Downing facing lengthy spells on the sidelines.
This has seen the former Lincoln boss adapt to his personnel crisis by shoehorning midfielders and full-backs into a back-three.
And the Blues have suffered dearly as a consequence by conceding 11 goals in their last five league games.
However, it may not be as easy at it appears to bring new faces into the club with the January window notoriously difficult to operate in.
As a result, Cowley may have to look for a short-term fix by looking towards the free agents, or at those whose current deals are set to expire.
Click through the list to see who could arrive on the south coast on a free transfer or for a cut-price deal.
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5. David Wheater - Former club: Oldham Athletic
Admittedly it's highly unlikely that the former Bolton Wanderers defender will arrive on the south coast this winter, but Cowley's hand may be forced if Pompey's injury woes continue. The Premier League veteran was last playing for Oldham Athletic in 2019/20 where he made 34 League Two appearances. (Photo by Pete Norton/Getty Images) Photo: Pete Norton
6. Contracts expiting in 2022
Similarly, there are a whole host of League One defenders whose contract expire at the end of this season. This then opens the possibilities for either cut-price deals in January or signing them on a pre-contract prior to the summer. Photo: Joe Pepler
7. Chey Dunkley: Sheffield Wednesday
Dunkley is vastly experienced in League One after impressive spells at Wigan Athletic and, now, Sheffield Wednesday. The centre-back has made 10 league appearances for the Owls this season and has scored once. (Photo by George Wood/Getty Images) Photo: George Wood
8. Bailey Wright: Sunderland
Bailey Wright has been an ever-present for the Black Cats this season, which may mean a new contract is just around the corner. However, Pompey could do a lot worse than bring the Australian to Fratton Park due to his experience and qualities in defence. (Photo by Pete Norton/Getty Images) Photo: Pete Norton