Copeland, alongside his rider Federico Zurlo, spent four hours with team Movistar's Spaniard in the hospital waiting room.
Ventoso crashed on the Quérénaing sector, at 115km to race when Fabian Cancellara (Trek-Segafredo) and Peter Sagan (Tinkoff) were distanced from the favourites, and reports suggested a disc brake from a Direct Energie team bike sliced his shin.
"He was still sitting there in the waiting room at 7pm when we left," Copeland told Cycling Weekly.
"I saw him when he came in, the cut was really bad, you can see that something sliced his leg. 'Look at the bottom of the cut,' Francisco said, 'You can see it's cut like a blade from a disc.'
“It looked as though a blade sliced him, but how? I'm not 100% convinced that it was a disc, it could have been aero spokes."
Given the cut on his left leg and that discs mount on the left side of bikes, Copeland said it becomes harder to believe that it could have been from a disc brake. However, he said it is possible that Ventoso tumbled and landed in such a way for it to happen.
The French Pro Continental team Direct Energie uses Shimano disc brakes, as do Italian WorldTour team Lampre-Merida. In Roubaix, both teams raced with the system.
"If this is the case [that it was caused by a disc], " Copeland added, "Shimano, SRAM and everyone else need to create shields. A protection must be made."
"We will keep working with our bike supplier Merida. We already have a cooling duct around the rear disc, something like this could be added on the front for safety.
"The UCI needs to make the decision on disc safety modification. It would be better for the riders. I would prefer it."
Copeland, however, wants to keep using discs brakes in his team. "I see discs as the way forward, the breaking is phenomenal."
The UCI said in a statement to Cycling Weekly that it "was very concerned to hear of the incident that occurred this weekend at Paris-Roubaix which resulted in the injury of Movistar rider Francisco Ventoso.
"The 2016 season marks the second trial year for disc brakes in the pro peloton and we will study this incident carefully.”
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