Negotiations between Barcelona and Konrad de la Fuente over a new deal have broken down with sources telling ESPN the American is keen to join former United States national team coach Jurgen Klinsmann at Hertha Berlin.

De la Fuente, 18, has been in talks with Barca over a contract extension for several months. The forward's terms expire in the summer but club sources said in November they were confident of striking an agreement with the U.S. youth international.

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However, De la Fuente's head has been turned by the interest shown in him by Hertha Berlin and the chance to play top-flight football in a league where many Americans have broken through.

German businessman Lars Windhorst recently upped his stake in Hertha to 49.9% after purchasing an additional 12.4% for €99 million. Germany's 50+1 rule prevents him from owning a majority stake in the club.

That transaction coincided with the appointment of Klinsmann as the first team's interim coach. It's his first major role since leaving the U.S. men's national team in 2016.

Windhorst's investment and subsequent cash injection means the club have money to spend on players in January, when a clear out of the squad is also anticipated.

Barca have offered De la Fuente a three-year deal with the option for another two years. During the first two years of the contract, he would be with the club's B team and then, in the third year, he would become a first-team player.

The Spanish champions believed he would accept those terms but learned earlier in December he was having doubts.

In a bid to get him to stay, he was promoted from the U19s to the B team for last weekend's game against La Nucia, which he started. But with the player still pushing for a move, despite the fact his parents and agents are in favour of him remaining at Camp Nou, he didn't feature for the U19s or the B team this past weekend.

Hertha are hopeful a deal can be done in January but for that to happen they must reach an agreement with Barca. Failing that, De la Fuente will be able to walk away next summer and the German club would only have to pay development rights of up to €700,000.

Germany has been a successful breeding ground for American and Canadian players in recent years. Christian Pulisic, Alphonso Davies and Tyler Adams are among several players to have enjoyed success in the country.

De La Fuente, who played for the U.S. at the U20 World Cup earlier this year, was born in Miami to Haitian parents, but moved to Spain when he was 10, eventually joining Barcelona's La Masia academy in 2014.

In an interview with ESPN earlier this year, he described himself as a "dynamic winger, who is fast, skillful, tricky and likes to take players on."