The Serie A giants will face Lyon in the Champions League on 16 Wednesday evening and are said to be on the hunt to find a replacement for Gonzalo Higuain in the summer.
And the report suggests that Ronaldo could dispel United’s hopes of signing Dembele if he were left struck by the Lyon striker.
Juventus are said to go to Ronaldo for advice on signing an attacker and they could make a move if the Portuguese international believes it would be a good choice.
Lyon president Jean-Michel Aulas has so far rejected several approaches for Dembele with the club struggling to finish in the top three.