Redknapp believes he has been a huge disappointment.
"I don't know what he has done at United really? If he leaves United, he's not exactly going to leave there thinking 'what an amazing job I've done at United'," he told the Mirror.
To be fair, he's gone there after they let him go for nothing when he was a young player. He's gone back there and listen, I know he's a good player. He's won the World Cup with France.
"But, he's not going to be up there when you're picking your best Manchester United teams. He's not going to get anywhere near those teams is he?"