Dutch rider Fabio Jakobsen is in a life-threatening condition in hospital after a huge crash on stage one of the Tour of Poland.
Jakobsen, 23, fell over the barriers and collided with an official.
“His condition is very severe. There is a danger to his life,” said race doctor Barbara Jerschina.
“Unfortunately, it is quite a serious injury to the head and brain. He has lost a lot of blood. He is very strong. I hope he will survive.”
An air ambulance was called to the finish line and Deceuninck-QuickStep rider Jakobsen was treated by doctors.
Jumbo-Visma sprinter Groenewegen, who was named as the stage winner before being disqualified, and several other riders also fell after crossing the line.
Jerschina said the race official suffered head and spinal injuries but was speaking when he was taken to hospital.
Cycling’s governing body UCI said it “strongly condemns the dangerous behaviour of Groenewegen”.
A statement read: “The UCI, which considers the behaviour unacceptable, immediately referred the matter to the disciplinary commission to request the imposition of sanctions commensurate with the seriousness of the facts.”
Jumbo-Visma said: “Our thoughts go out to Fabio Jakobsen and other people involved in today’s terrible crash in the Tour of Poland – crashes like these should not happen.
“We offer our sincere apologies and we will discuss internally what has happened before we may make any further statement.”
The podium ceremony was cancelled and the results of the 195.8km stage from Stadion Slaski have not been released.