Rooney said: "The fact that he's refusing to come in and train, it's going to be very difficult for him to come back in. There's a trust element there; he's going about it the wrong way. Maybe he's getting advised wrongly.
"But also for the team who's trying to sign him, in this case it looks like Liverpool, you have to wonder, is this the sort of player you want, who's going to desert his team-mates and a huge football club. It's a good opportunity, but it has to be done in the right way.
"There's the right way to do it and the wrong way. And I've been there myself when I've asked Manchester United to leave."