Kanu's new deal at Pompey looks like a formality after his agent revealed the striker is now "comfortable" with the terms on offer at Fratton Park.
Meanwhile, Pompey have sounded out Boro about bringing £12million-rated Yakubu back to the club where he was a 20-goals-a-season man in two Premier League campaigns until his £7million move to the north-east two years ago.
Despite Nigerian star Kanu's willingness now to sign a new one-year contract with additional options, Redknapp is still keen to add another striker to his squad despite already buying David Nugent and John Utaka for a combined £13million.
And those deals are the reason that Yakubu's agent Barry Silkman believes the player will be too expensive to complete an all-Nigerian front-line trio with Kanu and Utaka at Fratton Park.
Silkman told the Portsmouth News: "Yakubu will not come cheap. I honestly believe Pompey don't have the money to pay for him.
"Maybe Portsmouth thought the price would go down the closer it got to the (start of the) season. But Middlesbrough will look at the money Portsmouth have spent for David Nugent, Sulley Muntari (£7.2million) and John Utaka and think Yakubu is worth more."
Meanwhile the deal for Kanu, who turned 31 on Wednesday, finally looks to have been resolved after dragging on all summer.
It is believed that last season's top Pompey scorer, who will miss a large chunk of the season if he plays for Nigeria in the African Nations Cup in January, has agreed a one-year deal with a clause that stipulates he earns another year after playing 16 league games.
Kanu's representative Samuel Okoronkwo admitted: "It has been protracted, almost like toothache, and Kanu has had to say no to some Spanish teams who were very keen.
"But we managed to strike an agreement with Peter Storrie (Pompey chief executive) and we are comfortable with the terms."
The negotiations delayed Kanu's return to training until Wednesday but he scored twice on his debut as a substitute against Blackburn a year ago after hardly any pre-season preparation.
Okoronkwo said: "He will be ready for the start of the season.
"Kanu has been training hard behind the scenes over the summer and is raring to go."