El Mundo Deportivo says Spurs are insisting on their €45 million asking price for Modric, which is deemed too rich by Real.
The Londoners are willing to compromise if Real include Sahin in their offer. But both the player and coach Jose Mourinho do not want him to go.
For his part, Modric is becoming increasingly anxious about the situation.
Spurs are due to leave for the US on the 21st of July, with Real also traveling to LA on the 29th. Modric is sweating on a breakthrough before then.