Wigan Athletic boss Steve Bruce says Carlos Tevez and Cristiano Ronaldo are mad to be considering leaving Manchester United.
Ex-United captain Bruce said: "Once you leave Old Trafford you find it very difficult. Not many have gone on to do well elsewhere, whether they have been a reserve or have been there for 10 years. It's very difficult to adjust.
"Sir Alex Ferguson has to be the No 1 manager of all time."