Florian Wirtz knows what it is to be a wanted man. For many young footballers a summer where three of Europe's leading clubs (briefly) fought it out for his services might be enough to have their head spinning.

Germany's Rhineland clubs - namely Leverkusen, Koln and Borussia Monchengladbach - were all reported to have a gentleman's agreement not to 'steal' one another's youth talent, dating back to 2001, when Koln tracked and signed Leverkusen's then-12-year-old starlet Marco Quotschalla with the lure of an eight-year contract.