Pompey have been handed a goalkeeping headache with Mikkel Andersen set to return to Reading next week.
The 23-year-old had originally been lined-up for a season-long loan at Fratton Park.
But the Blues’ on-going administration problems ensured when he arrived on August 18 that it could only be a month-by-month deal.
In turn, the inability to have a loan from one transfer window to another saw it classified by the Football League as an emergency loan, which lasts a maximum of 93 days.
It means Tuesday night’s home clash with Leyton Orient will be Andersen’s final Pompey appearance.
Simon Eastwood is the only other recognised keeper registered with the first team, while Connor O’Hara represents the Academy.
Andersen has been the club’s regular stopper, with 17 appearances during his time at Fratton Park.
Whittingham is on the lookout for another new number one to come in as a loan replacement, focusing on the Championship.
And he is hopeful of securing a replacement for the Dane in time for the trip to Coventry City (November 24).
‘Mikkel has got to go back. We can only keep him for 93 days so are in the process of sorting out a goalkeeping loan,’ said Whittingham.
‘It will be his last game on Tuesday. That’s his time up so he has got to go back to his parent club. We can’t keep him.
‘I think it’s a blow. He has brought competition for sure with Easty and is a good lad who has done decent for us.
‘Hopefully we helped him out by giving him that experience as well.
‘We brought him back into the team at Bury. Easty hadn’t done a great deal wrong but I rely on John Keeley (goalkeeping coach) and what he says.
‘He said Mikkel looked superb in training and that is the way I want it to be with a lot of players.
‘If they are doing well in training and doing well in games then they will play.’
Eastwood himself has played four times so far this season, all in different competitions.
And Whittingham is looking for a new arrival from the Championship to provide a challenge.
He added: ‘We are looking at players in the Championship who are second choice or third choice.
‘With the money we have we haven’t got a lot of choice.
‘We’ve scoured the country – John has done a great job – and I’m hoping we can pull something off in time for when Mikkel goes back.
‘We are not looking at the Premier League. The problem you get there is obviously the money.
‘A few Premier League clubs have been kind to us and let people come at hardly any cost, but they are usually younger and they usually say they want them to play.
‘It’s just a case of trying to find the right one.’