Premier League - Spurs made move for Ferdinand
The Spurs boss is a big admirer of the former England captain, who began his career under Redknapp at West Ham.
Redknapp told The Observer how his quest to add players with more experience and leadership qualities to his squad led to an approach for the 32-year-old centre-back.
"I can't ever see us getting Rio now. I was interested. Last year, I tried. I tried at the start of the season," he said. "When he was on the teamsheet against Chelsea in the Champions League, I thought Man United had got a much, much better chance of getting a result and it proved that way."
That desire for more experience is what led to William Gallas signing on a free transfer last summer after leaving Arsenal, and why Redknapp made an approach for Everton captain Phil Neville in the January transfer window.
Redknapp said:"William has come in and given us experience and we've got Michael at the back but in the long term I still feel that you need to find another one or two if you're going to keep progressing, that type of real character, who has opinions and that will to win around the dressing room - a few leaders. You can't have too many at your club. That's why I tried to take Phil Neville from Everton in January."