The Mail on Sunday says while close to manager Harry Redknapp, £40million-rated Modric is sceptical that Spurs can compete with the elite in European football with 'old school' coaches Joe Jordan and Kevin Bond taking charge of practice sessions and inexperienced former players such as Tim Sherwood, Clive Allen and Les Ferdinand backing them up.
Modric's doubt was one of the major reasons behind his desire to join Chelsea last summer and why negotiations to improve his £45,000-a-year contract at Spurs are dragging on.
However, a source said: "It's not about money for Luka at the moment. He has just turned 26 and feels time is running out to play at the very top level.
"Spurs have a very good team but Luka has doubts over the way the squad are trained and prepared and whether they can be as successful as Chelsea in the next few years."