The revelation that he is, initially, only on loan is yet another twist in the saga that leaves Benjani Mwaruwari still in limbo, holed up in a Manchester hotel, after his move to Manchester City ran out of time on Thursday night.
But Pompey insist the two situations have no effect on each other - even though manager Harry Redknapp admitted the plan was always to sell Benjani to raise the cash to buy Defoe.
"The full documents will be signed and registered this week and this is a standard method when you have little time."
Redknapp said: "I honestly could not tell you the exact details but (at five minutes to midnight on Thursday) the two deals were dependent on each other with us getting £9million for Benjani and spending it on Defoe.
"I feel for Benjani because at the moment he seems to be the big loser in all this, but hopefully it will all be sorted out on Monday and I think he will end up as a Manchester City player.
"If not, from a greedy football manager's point of view, I'd be delighted to get Benjani back. I didn't want to lose him in the first place but, of course, I had to because it is good business to sell a 29-year-old and get in a lad of 25 who is always going to get you goals.
"The owner has spent a lot of money here already. He's been fantastic for me and it wouldn't be fair on him if he has to spend more now (with nothing coming back)."