The 64-year-old met with Daniel Levy on Tuesday to discuss Modric's future and the Spurs chairman gave Redknapp the same assurance that he has given him all summer - that the Croatian is staying.
"The situation is that he is not for sale," Redknapp said. "When I spoke to the chairman he said Luka definitely wasn't going and that was the end of the matter as far as he was concerned. Luka has to get on and play now. I need him back playing."
Modric did not train with his team-mates on Wednesday, but could play in Thursday's Europa League play-off second leg against Hearts if Redknapp thinks he is fit and focused enough to give a good performance.
"Will he play? Possibly. We will see how his hamstring is on Thursday. Certainly I'm looking to have him fit for the weekend against Man City."
Playing Modric in the clash - which Spurs lead 5-0 from the first leg - would mean he would not be able to play in the Champions League for Chelsea until February if he moves, but Redknapp could not care less.
"We are not in the Champions League so it won't affect us," Redknapp added. "I'm not bothered about anyone else. He is here, we love him, he is a great player so I need him back playing.
"He has to crack on with it now and I'm sure he will."
Redknapp also said he would block Modric's participation in Croatia's Euro 2012 qualifier against Malta next week if he continues to miss Tottenham's matches.
"He is not going to go away and play for his country next week if he doesn't play for Tottenham," Redknapp said. "Like all players, if they are not fit to play for their clubs they will not be going off on international duty."
Source: PA
Source: PA