Spanish champions Barcelona sold promising Croatia midfielder Alen Halilovic to Hamburg on Thursday, with the La Liga side including a buy-back option in the deal.

Halilovic, 20, joined Barca in 2014 from Dinamo Zagreb and spent the past season on loan at Sporting Gijon, who narrowly avoided relegation from Spain's top flight.

The attacking midfielder was left out of Croatia's Euro 2016 squad, while Barca have the option over the next two seasons to re-sign Halilovic from Hamburg for 10 million euros ($11 million).