The numbers behind Haaland's Dortmund release clause

RB Salzburg reached an agreement with Borussia Dortmund for a total of 21 million euros for Erling Haaland, one of Europe's most promising players. 

The Norwegian player has started off brightly, scoring an impressive amount of goals in his short time there, which is why his release clause is already worrying his current employer according to "Sport Bild". 

The source claims that the player's buyout clause if of 75 million euros, but it could only be triggered by the end of the next transfer window. 

Haaland will, therefore, be tied to Dortmund until at least 2021, which is when any team could poach him up if they are willing to pay the 75 million euros it would cost them... Mind you, it would not be the first time a club pays such an amount for a promising youngster.