Birmingham manager Gary Rowett has said the club risked losing Demarai Gray for £1-1.5m unless they inserted a release clause in the winger's contract.
Leicester City are believed to have triggered the England U-20's £3.75 release clause and Rowett - who left the 19-year-old out of today's matchday squad - told the Birimingham Mail the player insisted on having the release fee included in his new deal.
"In the summer we sat down with Dimmy and his agent - he had a year left. They were insistent that unless we put certain things into his contract to clarify the amount it would take to get him out that they would run the contract down and go on a tribunal in the summer."
He added the club had no choice but to inserting the clause or lose him for a cut price.