Ronaldo would like to see his young countryman at his new club in Spain.
Real Valladolid owner Ronaldo says that he would 'love' to take Vinicius Junior on loan from his former club Real Madrid, but admitted that such a deal would be 'very difficult'.
Ronaldo took over as the majority owner of Valladolid in September. His new side made a strong start to the season but have since dropped to 12th with just one win in their last six matches, and only two sides in La Liga have scored fewer goals.
In his attempts to inject some attacking verve, Ronaldo has been in touch with his former club to see if there would be any chance of taking Vinicius on loan - but he admitted that it was a long shot.
"I think Vinicius is great, I think he's a great talent, Madrid are lucky to have him and he's going to get it right," Ronaldo told Europa Press.
"I'd love to have him in Valladolid, but it's very difficult. He's got a lot of talent, and Madrid want him to stay in their squad. Florentino told me a deal would be difficult."
Real Madrid signed Vinicius Junior from Flamengo in the summer and he has been given several first team opportunities since Santiago Solari replaced Julen Lopetegui as manager.
He scored his first Madrid goal against Valladolid last month and got an assist on his Champions League debut against Viktoria Plzen.
He made his first start in the Champions League this week against CSKA Moscow, but Real Madrid were booed off after a 3-0 defeat at the Santiago Bernabeu.