He said: "We know he wants to leave and whether he writes it down on a piece of paper doesn't make any difference to our stance. He's a great player and we don't want to lose him."
Assistant manager Kevin Bond is in charge of the South African tour and says he has been impressed with Modric in training.
"Luka has been as good as gold," said Bond. "He is working hard in training and he is very much part of the group.
"It doesn't surprise me that a number of clubs want to take Luka Modric and quite possibly a number of our players. He is a fantastic footballer and it doesn't surprise me that other teams want him."
Meanwhile, Tottenham's hopes of offloading Giovani Dos Santos to Sevilla suffered a setback after the club's president, Jose Maria del Nido, said his club were only interested in a loan deal for the Mexico international forward.
