But John Marquis’ stay at Fratton Park is over.
Guy Whittingham admitted the Blues have to make their mind up whether to take the plunge and sign Jervis, who remains at Fratton Park.
Pompey have taken advice from Fifa, the FA and PFA over whether they would have to pay training compensation to his former Turkish side Elazıgspor if he signs.
The word from those football bodies are they won’t, without being definitive.
Jervis indicated the saga was nearing a resolution this week, via Twitter.
Now the Blues boss feels it is at a point where a decision has to be made.
He said: ‘We’re getting all the advice in the world there will not be any training compensation. That’s where it is.
‘It’s between that and them saying do it and us getting international clearance.
‘It’s not an easy decision.
‘But we’ve spoken to the FA, the PFA and Fifa and they are all saying it’s very, very, very unlikely. But they aren’t saying: “no there isn’t”.
‘That’s what we’ve got to make our mind up about sooner or later.
‘We have to decide whether to go for it – or it’s too much of a risk.
‘Jake is someone I’d love to add to the squad, for sure.’
Meanwhile, Whittingham indicated Marquis will return to parent club Millwall, with the striker’s current loan spell at Fratton Park set to expire.
He said: ‘I think he will go back. I would think so.
‘With John going back he’s probably a victim of circumstance, with David Connolly and Ryan Bird coming back in. They’ve done okay, and that’s why John will go back – especially if Jake comes through as well.’