Kramaric, who played an hour of Croatia's 2-0 World Cup Group D victory over Nigeria, has been widely linked with a return to the Premier League to join Newcastle United - although Bayern Munich is also reported to be chasing his services.

Formerly of Leicester City, Kramaric had a stellar season at Hoffenheim, in which he scored 13 goals. His services resulted in interest from Italy during the January transfer window.

Hoffenheim, which earned a spot in the group stages of the Champions League next season, is prepared for bids for its star striker and a potential price tag has now been revealed.

"I never rule out anything, that's not in our business," Rosen said. "We had an offer of €30m for Andrej from Italy during the winter break. That was not an option for us. But what happens if €50m is offered I cannot say."

Capped 32 times by Croatia, the 27 year-old spoke about his future before the 2018 FIFA World Cup in Russia and refused to be dragged into speculation.

"I saw what the media have said [about Bayern links] but take it easy, there is plenty of time," he said. "My priority is the World Cup now. There is plenty of time to discuss a potential transfer."

Croatia next faces Argentina in Group D - a victory can seal a spot in the knockout stages - before tackling Iceland in its final group match.