Teenager Edo Maas may never walk again after he was involved in a collision with a car during the Piccolo Lombardia earlier this month, his team say.
The Dutch Sunweb rider, 19, broke his back in the collision with the car, which had entered the closed course on a descent.
He underwent surgery, but Sunweb said "it remains unlikely that functionality in his legs will ever return".
The team called for improved race safety for teams and riders.
Maas' collision was one of a number of serious incidents in recent months, including the death of Belgian cyclist Bjorg Lambrecht during the Tour de Pologne in August.
Sunweb - who added that "fighting power and hope prevails" for Maas - want cycling's governing body, the UCI, to implement changes.
"While this won't undo this devastating tragedy, we once again call upon our governing body to prioritise all of their time and resources on securing and ensuring the implementation of safe race conditions for teams and their riders," the team said.