Reports have indicated Aaronson will cost Leeds in the region of £24.7million (€29m) when the transfer officially goes through on 1 July.

He has committed to a five-year contract and will strengthen the Leeds midfield after the Premier League side avoided relegation on the final day of the season thanks to a win at Brentford.

Former Philadelphia Union player Aaronson, 21, has earned 18 caps for the USA and scored five goals for his country.

He joined Salzburg in January 2021, fresh from being named in the MLS Best XI for the previous season, and had a key role as head coach Marsch's team wrapped up a Bundesliga and cup double.

While Marsch moved on to RB Leipzig at the end of that season and later arrived at Leeds, Aaronson stayed on in Salzburg and helped Matthias Jaissle's side reach the last-16 stage of the Champions League.

Salzburg also landed another domestic double, and Aaronson believes the time has come to move on to bigger things.

He told Salzburg's website: "I can barely believe that it was only a year and a half I spent playing for FC Red Bull Salzburg.

"This big step from my homeland in the US to Europe was made an extremely easy one by everyone at the club, from the players, coaches and all the staff, and I had a fantastic time here. To come to Salzburg was totally the best decision I could have made!

"After our strong performance in the Champions League and winning the double, it's the perfect time for me now to move to a new and really big league."