The 25-year-old Italian was knocked unconscious in the accident, and given medical attention at the side of the road, before being taken to Zamora hospital, 50km north of the stage start in Salamanca, where he's in a "good and stable condition", according to his team.
"He's also suffered a deep cut to his left eyebrow, which required stitches, and some of his teeth are broken.
"He's able to interact with the team's doctor, Michele De Grandi, and the CAT scan has excluded neurological problems," continued the UAE press release.
"At this point, we are waiting on medical advice on when he can be discharged from the hospital."
Petilli spent five days in hospital last year after he crashed out of Il Lombardia in early October.
On that occasion, he fractured his neck and a vertebra, as well as breaking his collarbone and shoulder, but returned to racing at the Tour of the Alps in April this year.
LottoNL-Jumbo renew with Van Emden and Lindeman
The team announced on Tuesday that Van Emden will return for three years, while Lindeman has signed a new one-year deal.
"I can't think of a reason to leave," said Van Emden, who joined the team in 2008 when it raced as Rabobank.
"They know what they can expect of me, and I know what I can expect of the team. It's nice to see the development of the team closely and contribute to it. Thanks to their guidance, I'm still improving myself on some points."
Van Emden, 33, is a time trial specialist who won the final individual time trial at the 2017 Giro d'Italia – the same year he won Dwars Door West-Vlaanderen.
In August, at the European time trial championships in Glasgow, the Dutchman had to borrow one of compatriot Ellen van Dijk's skinsuits after his suitcase was lost en route to the race.
Lindeman, 29, joined the team in 2015 from the Rabobank Development Team. He's notched up four pro wins since then, including a Vuelta a España stage in 2015.
"I'm happy with the contract extension," Lindeman said. "I have my role, and I'm appreciated. I'm here to support the leaders, and sometimes I get my own chances."
It was also announced that seven-year veteran of the team, Robert Wagner, would not return next year, as he "will leave LottoNL-Jumbo for another team", which the German has yet to confirm.
Coquard set to return to racing
The French sprinter crashed out on stage 3 of the Tour du Limousin in mid-August, fracturing his shoulder blade.
"For two days, the only way I could get any relief was by lying flat on my back," Cocquard said on his team's website. "I stayed in bed, watching films and a bit of cycling on the TV, but that didn't last long. I'd broken my shoulder two years before, so I knew that it was something that healed quite quickly, no matter what anyone says.
"After six days without cycling, I was able to get on the home trainer, despite a bit of pain, and was able to find a position that was manageable. I was then able to do two one-hour sessions a day for a while, and now I'm able to ride for three hours without any pain, so I hope to be back out on the road at the end of this week," said Coquard.
The 26-year-old, who this year has won stages at the Tour of Oman, the 4 Jours de Dunkerque and the Baloise Belgium Tour, hopes to make his return to racing at either the Tour de l'Eurométropole in Belgium on September 22, or the GP d'Isbergues in France on September 23.
Zhandos Bizhigitov renews at Astana
"I'm very happy to continue working at Astana Pro Team," Bizhigitov said in a team statement.
"The first two years flew by very quickly. I was able to get some experience, but I think more work has to be done to attain some really good results," he said.
"Next season I want to continue working hard, to get more experience and to get to the next level to be ready for bigger goals."
The 2017 Kazakh time trial champion has proved to be a vital support player within the team, and finished his debut Grand Tour at the Giro d'Italia last year.
"I believe that Zhandos can make solid progress next season," said team manager Alexandre Vinokourov.
"He has everything he needs to do it: both the talent and the desire. This year was not his best season when it comes to personal results, but he was really strong as a helper at a number of races in which Astana were successful.
"I think, having gained such experience in his first two years as a professional, the big results will come next season."