Marini, whose rear wheel was seen high in the air as he tried frantically to avoid hitting the back of Bezzecchi, will now be taken to a hospital for further medical checks.

Pole qualifier Bezzecchi rejoined at the back of the field after the Turn 1 incident, before fighting his way up to fifth.

Marini's injury is the second of the day with Alex Marquez fracturing ribs in qualifying.

Like Marquez, Marini is now almost certain to also miss next weekend's Japanese round at Motegi.

The FIM Stewards later handed Marini a long lap penalty, to be served in the Italian's next MotoGP (Sunday) race, for 'aggressive contact with another rider at Turn 1 which severely impacted his race'.

"It is a type of racing accident that can happen if you have two riders fighting at the top positions," said VR46 team manager Pablo Nieto. "We are very sorry, also because Luca suffered a fracture of his left collarbone and will have to undergo surgery in Italy in the next few days.

"We wish him the best and look forward to seeing him on the track as soon as possible to continue fighting with the strongest guys at this level."

Marini wasn't the only rider on the ground at turn 1 with Stefan Bradl clipping the back of Augusto Fernandez before bringing down Pol Espargaro. Bradl later explained that Fernandez 'closed the door' in front of him and he couldn't avoid the contact. The FIM Stewards deemed it to be a 'race incident'.