Yamaha has announced that World Superbike rider Michael van der Mark will replace Valentino Rossi for the next MotoGP round at Aragon.
Rossi broke his right leg in a motocross training incident in the lead-up to last weekend's Misano race, and was forced to miss his home event as a result.
While his minimal recovery time was estimated as "30 to 40 days", the Italian had previously not ruled out attempting to ride at the Aragon round later this month, which will take place 22 days after his accident.
But team boss Lin Jarvis has now confirmed Rossi will not be fit enough in time for the event and, with Yamaha obliged to field two bikes at Aragon, 24-year-old Dutch rider van der Mark will instead take his place.
"It being virtually impossible for Valentino to be fit to race in Aragon, Yamaha decided to search for a capable replacement from within its own pool of contracted riders," said Jarvis, who previously said four riders were in contention for Rossi's seat.
"We decided that Michael van der Mark should have the opportunity this time around.
"It is never easy to step in to replace another rider and even more difficult to replace Valentino Rossi, but we believe that Michael has all the credentials and experience to do a good job.
"We will give him our very best support and wish him every success for this exciting opportunity."
Van der Mark joined the Yamaha World Superbike outfit for in 2017 from Honda with which he won the 2014 Supersport title and scored nine Superbike podiums.
He currently sits seventh in the WSBK standings, two places behind works team-mate Alex Lowes - who served as Bradley Smith's MotoGP stand-in at Tech3 Yamaha last year.
"I've never ridden a MotoGP bike before, so this will be a completely new experience for me," van der Mark said.
"I'm very curious to see what it feels like to ride on such a machine.
"I realise that it won't be easy going straight into an official practice session without any prior testing.
"Nevertheless, I'm very grateful to Yamaha for the opportunity. I'm sure it will be a great learning experience."
Rossi's absence from Misano means he is 42 points adrift of joint MotoGP championship leaders Marc Marquez and Andrea Dovizioso with five races to go.