The Colombian rider's form early in the season left an impression with Roglic after his success in the Tour du Var and Tour de la Provence in February, and victory on the last mountain stage at Paris Nice.
Commenting on Quintana's move to Arkea-Samsic from Movistar, he said: "I think it was a good decision because at the beginning of the season he had some very good victories.
"But we must see how the return is for us all at the start of the calendar. I don't think he has any disadvantages because he's at Arkea.
"He has already shown how strong he is this year. In the Tour it will be difficult to stop him," he told Colombia newspaper.
Quintana discusses Tour de France preparation and ambitions
Roglic's team Jumbo-Visma is being led in tandem with joint-leader Steven Kruijswijk and will also feature Tom Dumoulin in his first Tour for the team. George Bennett, Sepp Kuss, Wout van Aert, Tony Martin and Robert Gesink will provide support.
"It's nice. We're stronger as a team so it's a good thing," said Roglic.
"I think the three of us are really capable of being leaders in the Tour. In the end, what we do is train to achieve the goals as a team and we will do that. I have trained with them and everything has gone well.
"The strongest will be the leader," explaining that it is not yet certain who will be the priority for the team. "I hope I can, but we will see who is best."