Redknapp believes Bale was among the very best footballers at a certain point in his career and he could get back to form under a manager who wants him.
Bale returned to England to play for Tottenham Hotspur before the beginning of this campaign in an attempt to revive his career which stalled in recent seasons at Real Madrid.
Many thought the Wales superstar would have added firepower to the already existing lethal strike force of the North Londoners, but that has not been the case.
Bale has made only six appearances in the Premier League and 15 in all competitions.
The 31-year-old was left out of the matchday squad in Tottenham’s 5-4 defeat in the FA Cup fifth round game on Wednesday.
Redknapp, who once managed Bale at Tottenham before his then record move to the Santiago Bernabeu, believes the former Southampton man was up there as the third best player in the world after Lionel Messi and Cristiano Ronaldo
“At the time I thought Gareth Bale would be an amazing signing” Redknapp said on Friday’s talkSPORT Breakfast.
“I could see that forward line, Son, Bale and Kane, I thought ‘oh my God they are going to be scary together’, but for whatever reason it hasn’t worked for Gareth.”
“I don’t know what the problem is with Gareth at the moment. He’s not the most confident of boys.”
“I know he’s been one of the top players in the world, let’s be honest, there was a spell where for me he’d probably been the third-best player around behind Messi and Ronaldo, he was that good when he was at his best.”
“But he’s still not a very confident boy. He’s one of those lads who, no matter how great you are, it doesn’t change his personality, and he’s a very quiet lad. He needs confidence and he needs somebody to believe in him.”
Redknapp continued on Bale: “At the moment he’s had ten minutes here, five minutes there, when he starts he gets subbed, and when he gets subbed it’s all, ‘we were better in that last half hour’ after Gareth has come off…”
“All the signals he’s been getting [from Mourinho]…”
“I’m disappointed with how it’s gone for him. I was really expecting big things from Gareth when he came back.”
