Mark Catlin has warned Jake Jervis may not receive the Pompey green light until next week.
The Blues have spent the past seven days waiting for the Turkish FA to grant international clearance for their new signing.
Initially, the club were hopeful the 23-year-old would be available for selection for Saturday’s visit of Mansfield.
However, under Fifa regulations, the clearance has a maximum of 15 days to be signed off.
That deadline arrives in the middle of next week. In the meantime, there has been little movement from the Turkish footballing authorities.
The frustration continues for Jervis, who has been embroiled in a long-running stand off with former club Elazigspor.
It wrecked his hopes of signing permanently for Pompey back in November while he continued to train with the squad.
Now, after being recognised as a free agent this month, the striker’s Fratton Park registration has been completed.
But it could be next week before he makes his second Blues debut.
Chief executive Catlin said: ‘We have heard nothing more about his international clearance.
‘Regulations state it has to be completed within 15 days – which is next week sometime.
‘So, obviously, the danger is he won’t be available this weekend to face Mansfield.
‘Some governing bodies are easier to deal with than others, I think it is fair to say.
‘Associations like Wales, Scotland, Spain, France and Germany deal with it computerised and it is pretty much instant.
‘We have done all we can to push it through but Turkey, at the moment, don’t appear to be doing a lot.
‘My view is it should be instant in this day with the age of modern technology. The wait is crazy.
‘We have a player here wanting to play football but can’t until the Turkish authorities give him the go-ahead.
‘As it stands, we have no idea when it could go through.
‘If I knew that I would not be at Portsmouth, I would be betting winners on the horses!’
Pompey completed on-line documentation applying for Jervis’ international clearance on Wednesday last week, ahead of signing him until the end of the season.
It was then ratified by the Football League and sent to the Turkish FA to complete.
In the meantime, Jervis has continued to train with the Blues in the hope he will soon be able to re-start his stalled career.
And Catlin has every sympathy for a striker who scored one goal in three appearances during a Pompey loan spell last season.
He added: ‘It is extremely frustrating for the board, the manager and the fans, but especially Jake himself.
‘Whatever hair he has got he is pulling out. He has not played for so long.’