Standard Liege president Luciano D'Onofrio admits they face selling star midfielder Axel Witsel.
The Belgium international is a target for Liverpool, where football chief Damien Comolli is a big fan of the free-scoring midfielder.
"What is the value? I do not know, it depends. We sold Marouane Fellaini to Everton for €20 million, Witsel is a player of that level," said D'Onofrio.
"Let's say 12, 15, 18, 20 million.
"Will he again be with us at Standard Liege next season? He has many offers, it will not be easy to hold him in Liege."
