Modric has been fined two weeks wages after he refused to train with the squad last week and missed the club’s pre-season tour of the U.S., seemingly in an attempt to force through a move to Real.
“The situation as it stands is he is under club discipline for not being present,” said Spurs boss Andre Villas-Boas.
“We don’t know what advice he is receiving.
“There is a sense of respect for what he has done in the past but the chairman feels that the fact he is not present is not common professional behavior.”
The Spanish champions have so far offered 27-million pounds for the Croatian playmaker and insist they have not been communicating with Modric.
The Daily Mirror reports that PSG are looking to exploit the impasse, with the French side confident of landing the player should they meet Tottenham’s asking price.
The Qatari-backed club has invested heavily this summer, splashing out to sign Thiago Silva and Zlatan Ibrahimovic from AC Milan as well as Ezequiel Lavezzi from Napoli.