The Pompey boss is looking to strengthen things at the back at Fratton Park and was reported to be lining up bids for Manchester City centre back Richard Dunne and Tottenham defender Younes Kaboul.
Redknapp had been in talks with Dunne over a possible move South but it appears the appointment of Mark Hughes as the new boss at the City of Manchester Stadium may lead Dunne to remain at the club.
"I think we might be struggling on that one" Redknapp told The News.
Redknapp has also reported that the fee Tottenham are asking for Kaboul is excessive.
"I was interested in him but what they want is more than we are willing to pay, so there is nothing happening," Redknapp explained.