Ronaldo left United for Real Madrid in a record £80million move in 2009. The Portuguese star will make his first return to Old Trafford on Tuesday as Real Madrid face United in the Champions League.
"It would be a big ask for many reasons. I would love to see Cristiano here. I could see it," Vidic told the Sun.
"He is a United supporter. Even though he left he still follows United and still misses the club and the environment here."
Vidic believes Ronaldo is a better player than Barcelona's Lionel Messi.
He said: "They are both great players but, in recent years, Barcelona have won more trophies and I think that is why people have put Ronaldo to one side.
"The way he plays, he can play in England, he can shoot with his left, his right, he can jump and head the ball. He can dribble, he can do everything.
"I don't say Messi cannot do that but the way Barcelona play suits his style.
"Ronaldo has been changing games for the last four years for Madrid.
"Every time he walks on the pitch he wants to score. He has that hunger in every game."