Reigning MotoGP world champion Marc Marquez suffered a broken arm and possible nerve damage after being struck by his own bike in a high-speed fall during the season-opening Spanish Grand Prix.
The eight-time world champion fell off late in the race after mounting a comeback ride following an early error, and a heavy impact with the tarmac was followed by a collision with the front wheel of his Repsol Honda, before cart-wheeling into the gravel trap on the outside of Jerez's Turn 3.
"Marc Marquez has suffered an injury it seems from a direct impact of the tyre to the right arm, resulting in a fracture to the shaft of the humerus, a complete fracture, although it isn't completely displaced, with some possible paralysis of the radial nerve, although we're not certain," said MotoGP traumatology specialist Dr Xavier Mir.
"This injury has been immobilised here for when they decide to move him to Barcelona to carry out a definitive treatment."
Honda confirmed that the 27-year-old Spaniard will undergo surgery on the injury today once he has travelled to Barcelona, and he looks certain to miss next weekend's second race of the season, which will also take place at the Andalucian circuit.
The injury is likely to prove a decisive factor in Marquez's hopes of winning a fifth consecutive MotoGP title and a seventh in the last eight years, with points at a premium this season due to the shortened calendar.
More than four months after the season was due to get under way in Qatar, MotoGP finally resumed following the coronavirus pandemic in Spain, where seven of the 13 confirmed races this season will be staged.
Marquez made a strong start to overtake Yamaha's Maverick Vinales early and lead the pack, only to lose control at Turn 4 and just prevent himself from falling after tracking through the gravel trap.
After recovering from 18th position, Marquez had his sights on second place and was bearing down on Vinales once again when he crashed, allowing his fellow Spaniard to ride home to second place behind race-winner Fabio Quartarao, who led home a Yamaha one-two to become the first French MotoGP winner since Regis Laconi 21 years ago.
The win for the Petronas SRT team marked the first for a satellite Yamaha team in the MotoGP era, with Andrea Dovizioso securing third with a late move on fellow Ducati rider Jack Miller just two weeks after having surgery on a broken collarbone.