Fermin Aldeguer has been taken to hospital for further checks after his violent Assen MotoGP practice crash.

But his Gresini Ducati team-mate Alex Marquez appears to have escaped further injury in his own accident at the same spot on the Dutch track, which caused the Friday afternoon session to be red-flagged.

Although Aldeguer's initial low-side fall at the Duikersloot right-hander looked relatively innocuous, it increased in severity when he hit the gravel and began tumbling.

He was in clear discomfort afterwards and taken from the scene on a stretcher, and is now heading to hospital for further checks on his chest and back.

Marquez is attempting to complete his first full racing weekend since suffering neck and collarbone injuries in his frightening Catalan Grand Prix crash a month ago.

He returned for last weekend's Czech GP but withdrew after qualifying.

His Assen crash happened at the same point on the circuit, and he struggled to get up initially, prompting the session to be red-flagged until he could be helped away by marshals.

But Gresini said Marquez had escaped with "a contusion to his right shoulder and abrasions to his left arm" and there was no further damage spotted on a shoulder x-ray.