Spurs have been linked with an audacious approach for their former player, whom they sold to the Spanish champions for a then world record £85m in the summer of 2013.
An agreement is expected to be reached between the two parties in the coming days as manager Jose Mourinho is keen to add more firepower to his attack.
Bale’s days in Madrid are numbered as he has fallen out of favour under manager Zinedine Zidane amid a combination of poor form and fitness issues.
Tottenham’s star has faded since the highs of last year’s Champions League final appearance, and Redknapp, who helped covert Bale from a marauding left back into one of the world’s best wingers, is adamant a return to North London will augur well for Mourinho’s side.
"It would be a fantastic signing for the club and it would be great for Gareth to get back playing again. He's such a talent, such a great player and its waste to see him not playing," Redknapp told BBC Radio Wales.
"To get back to Tottenham could just turn their season around. They've been quite average in the last six months or so. End of last season and obviously got beat on Sunday by Everton. They need that little bit of magic Gareth can bring.
"If he went there [or] Manchester United... wherever he went, he'd make a massive difference."
