But Mark Catlin is adamant the Blues have learned from previous loan departures thanks to club callbacks.
Pompey has already lost Ben Thompson, Andre Green and David Wheeler in such circumstances.
In the case of Thompson, this was decisive for the outcome of the 2018-19 season.
Catlin points out that the Blues are now operating with fewer players on loan in a tight squad of 22.
And he insists that numbers like this allow recruiting flexibility in the January transfer window as well.
He said: “A lesson learned over the years is that lending can get stronger, but it can also be very disruptive, especially in January.
“Nowadays clubs tend not to loan players unless they have a recall in January, so if you are doing well and playing well, chances are they will recall them.
“Loans can be good, as we’ve seen we’ve had great loan signatures over the years.
“However, you still run the risk that by doing well they will get a callback in the January window.
“Sometimes we fall victim to our own success doing so well, which by default means players are doing well – and clubs tend to want those players to come back in January.
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“It’s important to point out that in our team of 22 we have two loans and a short term contract that expires in January.
“This is probably the optimal number to give you that flexibility in moving the chess pieces.”
Rasmus Nicolaisen is currently the last remaining lender to Pompey.
Even then, there remains the danger that he will be recalled by FC Midtjylland this month due to dissatisfaction with his number of games.
As Jordy Hiwula’s short-term deal expires on January 20 – the Blues are keen to keep the forward.
Catlin added, “Cam was a great addition to our squad, but when you sign a player in June / July / August, you don’t know if they’ll be good.
“So you need that flexibility or you could be stuck in the middle of the table with 22 players and no flexibility to move this team in January.
“It has its pros and cons.
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