Reigning MotoGP world champion Marc Marquez broke a bone in his arm after a heavy crash in the season-opening Spanish Grand Prix on Sunday.
The Spaniard, who was lying third in the race, lost control of his Honda and came off his bike which then hit him on the arm as he and the machine bounced across the infield gravel.
Marquez was put into a neck brace and taken away from the track in an ambulance.
His team tweeted: "A fall at Turn 3 while fighting for the podium has resulted in a broken right humerus for @marcmarquez93, who will travel to Barcelona for surgery."
Fabio Quartararo became the first French rider to win a Moto Grand Prix since 1999.
Marquez, 27, has won the MotoGP world title six times.