Keller is crossing his fingers Tottenham have the ambition.
"They have been in this position for the past 20 or 30 years," he argued.
"You can't cut corners and expect to compete at the highest level.
"You can't sell your top players if you want to compete with teams that don't.
"History says of course they will sell Modric. He will get mad enough and finally someone will give them a number that they can't turn down.
"Until that changes, everyone thinks that is what will happen."