Interested clubs must negotiate with Bologna if they're to sign Josh Zirkzee this summer.

The Holland international has been linked with AC Milan, Manchester United and Arsenal. While Zirkzee's deal carries a buyout clause, it only applies to former club Bayern Munich.

Bologna chief Marco di Vaio says: "It only applies to Bayern, detailed. For the other clubs the price is open..."

Bayern can buy back Zirkzee from Bologna for €40m.

However, the young striker has intimated a willingness to remain in Serie A next season.