Alex Lowes will miss Sunday's Aragon Grand Prix following his crash during MotoGP's third practice session on Saturday.
The British rider, filling in at Tech3 Yamaha for the injured Bradley Smith, had a highside at Turn 16 at the start of the session, and sat out the rest of the day's running.
While Lowes escaped fractures, he had lower-back and wrist pain and was unable to bend his significantly-swollen left foot, and postponed a decision on whether he would continue to Sunday morning.
Due to return to his regular World Superbike Yamaha next weekend at Magny-Cours, Lowes ultimately elected to prioritise being fit for that event rather than trying to start his third MotoGP race.
"These bikes are hard enough as it is without being injured," he said on Saturday evening.
"It's not my main championship, I'm doing it for fun and experience.
"I couldn't ride today and we'll see what happens for tomorrow.
"I'm paid to ride next week for the World Superbikes, so it's more important that I try to get fit and good for them."
The identical twin brother of Moto2 race winner and 2017 Aprilia MotoGP rider Sam, Lowes made his debut at Silverstone earlier this month - scoring points on debut with 13th - and also raced at Misano.
Smith is working towards being fit to return for the next round at Motegi in October, which Lowes would be unable to take part in due to a clash with the WSBK round at Jerez.