Modric has made no secret of his desire to leave White Hart Lane for Chelsea this summer, but Spurs chairman Daniel Levy has rejected all offers for the player and has repeatedly insisted he will not be leaving the club. Redknapp, though, has suggested he would not be averse to a deal.
"You either sell him, go out and bring three or four players in and have a better team, probably, in all honesty, or you keep him," he said. "When someone comes along and offers to treble your wages and gives you the chance to play in a team that can win the Champions League, it's not easy. He has had his head turned and it's difficult for him."
Tottenham were left short when Dimitar Berbatov left for Manchester United in 2008, but Redknapp insists Levy will not allow a repeat.
"He won't do that, no chance," Redknapp said. "Daniel wants to keep him and it's looking like we could get one or two players in over the next few days."
Redknapp confirmed Spurs have held talks with Real Madrid over Lassana Diarra but reiterated that he does not expect Scott Parker to join from West Ham.
He said: "I like Scott Parker but it's not an easy deal. We'd have to pay £7 million or £8 million, then there's his wages and he's 31 so it's not an easy deal for someone to do."
Emmanuel Adebayor is likely to be first through the door with talks over a loan switch from Manchester City ongoing. Redknapp has revealed he has a good relationship with Adebayor after he defended his controversial goal celebration against Arsenal two years ago when he raced the full length of the pitch to celebrate in front of the travelling support
"When he was at Arsenal he was almost unplayable and if he comes here that's what we are looking for him to do," he said. "There's no reason he can't do that.
"He was fantastic against us in Madrid last year. We couldn't handle him and if he's at it and he comes here and really wants to play, then he could be sensational. I stuck up for him when he scored that game (against Arsenal).
"They had been abusing him all game and when he scored, what was he supposed to do? You stick it up them don't you and that's what he did. He rang me and said that he appreciated it. I'm sure I'll get on with him if he comes here."
Redknapp feels he will be popular with the Spurs fans. "I'm sure they will take to him because he fell out at Arsenal. Arsenal fans hate him so Tottenham fans will love him. He upset them so he'll be a hero here."