The north London club fought a ferocious battle with Chelsea to hang onto the Croatian last summer and the playmaker looks set to be at the centre of another transfer saga this year, with Manchester City and Paris St Germain the latest clubs linked with the player.
Spurs reluctantly agreed to sell Dimitar Berbatov and Michael Carrick to Manchester United under Martin Jol and there are no shortage of admirers for their current stars like Modric and Gareth Bale, who has reportedly been attracting the attention of Barcelona recently.
Redknapp last week admitted Modric could leave this summer, but insisted the 26-year-old must stay to prevent the club sliding into obscurity.
"Once you start selling your best players you're finished," Redknapp said. "I don't know why Tottenham should be seen as a club that will sell its best players. We are not looking to sell our best players. We are looking to build a team here, not dismantle.
"The chairman made a stance with Modric last year - the stance was that we are looking to build, to add to the group we've got and improve for next year, not to go backwards. If we go backwards, we're going nowhere basically are we? We will slump back into mid-table mediocrity and we don't want that."