The Croatian forward, 24, has scored 37 goals in 44 league starts for Dinamo and is expected to feature strongly in his country’s European Championship campaign.
His performances have not gone unnoticed and several clubs from across Europe are understood to be keeping tabs on his situation.
German teams including Schalke and Stuttgart, as well as Italian duo Fiorentina and Torino, are believed to be on the case.
A host of English clubs are also thought to be monitoring things, especially as Cop has scored six goals in his first three games this season.
Agent Simon Conning is working on behalf of Premier League clubs to broker a deal which is believed to be in the region of €5m.
Sporting, meanwhile, are understood to have stepped up their interest aleady with an offer of €3million.