Beattie will face Rooney tomorrow night in the Champions League.
He said: "Rooney went to Manchester United in the summer and I went in during the January transfer window - but we did play together for England.
"He is a fantastic player. We sort of pinned all our hopes on him during the World Cup. He had a hell of a lot of pressure on him at that point, whether it was unfair pressure or not.
"But he was in tremendous form last year for United, and obviously a fantastic player and someone that you admire and respect.
"It must be difficult to be playing your football with all that is going on around him just now, but it is something that he has to deal with."