BK Hacken sports director Martin Ericsson expects Momodou Sonko to leave for record money.
Liverpool, Barcelona and Atletico Madrid are all interested in the youngster.
Ericsson told Gteborgs-Posten: "We absolutely expect it to be our biggest sale if there is a sale. We'll see, but we're confident as a club in this and it just feels inspiring and fun.
"We expect that it will become concrete and then we will see together if it is the right package. We have a very good dialogue about this and we take it one day at a time and evaluate it.
"Everyone has to be on board for it to become something and it is also important to us that it is a good next step. Then of course we keep him too if possible."