Chris Froome's Vuelta a Espana challenge is hanging in the balance after the British rider admitted he was unlikely to start stage 12 following a crash on Wednesday.
Team Sky's Froome, the double Tour de France champion, crashed out on the first climb of the gruelling 11th stage, suffering a heavy cut to his right leg and eventually dropping down to 15th overall.
The 30-year-old now trails new leader Fabio Aru by seven minutes and 30 seconds, and suggested he may have to withdraw from the year's final Grand Tour.
"Knocked sideways into a barrier and stone wall today," Froome tweeted. "Further scans in the morning [on Thursday] but start unlikely as I can't walk without crutches."
Froome had been bidding to become only the third rider to claim the Tour de France-Vuelta double in the same year. He started Wednesday's stage in eighth position, one minute and 18 seconds off the pace.
But the crash meant he finished almost nine minutes behind Spanish stage winner Mikel Landa, with Froome later adding: "I did my best to hang in there as best I could with the hope of continuing. Thanks to the whole team for the support, especially Geraint Thomas for sticking it out with me today."