Corluka reckons playmaker Modric will quit the club this summer with Manchester United and French side Paris St Germain ready to pay £30million.
He said: "We all know it will be very difficult for Spurs to keep Luka because they do not have Champions League football next season.
"Luka is one of the best players in the world and the kind who wants to play in the best competition.
"Not getting into the Champions League will cost Spurs next season. Even though they were unlucky to get fourth place and still not be there.
"I have followed the stories about Luka moving and that is just a reflection of what a great player he is.
"He showed some loyalty by staying at Spurs last season when other teams wanted him. I only wish Luka the best. If he wants to go fine.
"This tournament is a great chance for everyone to see how good Luka is."