Ronaldo makes his first return to Old Trafford on Tuesday night as his Real Madrid side meet United in the second leg of their Champions League last-16 tie. And Vidic, who played alongside the Portuguese before his record £80 million move to the Bernabeu in 2009, is optimistic they might be United team-mates once again.
He told the Daily Telegraph: "He (Ronaldo) is a United supporter and still follows United, he still misses the club and the environment here, so I wouldn't be surprised to see him come back."
Vidic continued: "It would be a big ask for many reasons, but I would love to see him here.
"I don't know what atmosphere he has at Madrid, so I can't really talk about that, but all I can say is that I enjoyed playing with him, he enjoyed it here and it will be great to see him."
Vidic believes Ronaldo is the equal of Barcelona striker Lionel Messi, who is regarded by many as the best player in the world.
Former Serbia international Vidic added: "They are different players, totally different.
"But in recent years, Barcelona have won everything and I think that's why people have put Ronaldo to one side.
"I have played with him and trained with him and I know how many sacrifices he has made to be where he is.
"He worked so hard on everything and people forget that."
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