He has a contract with the Old Trafford club until 2012 after extending his deal last year.
United have insisted they have no intention of selling their prize asset but his recent comments to a Spanish TV station hinted he may be thinking otherwise.
"I'm very happy here but let's see after the Champions League final what happens," said Ronaldo last week.
But, despite the player's remarks and the continual rumours about the two parties joining up, Schuster calmed talk of a potential bid after his side's final game of the season against Levante on Sunday.
"I don't waste time on these things," he added. "I think about who could come and not on speculation.
"We are going to look at what we need and then see."
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