Newcastle United legend Alan Shearer believes Wayne Rooney should consider leaving Manchester United if he is no longer happy at Old Trafford.

Rooney has not been Sir Alex Ferguson's No.1 choice in the striking position since Robin Van Persie's arrival at Old Trafford, with the 27-year-old having to play in a wide variety of roles.

The England international was substituted with 20 minutes remaining in the English Premier League game against West Ham, even though Man United were a goal down at the time.

Van Persie duly scored the equalizer and Shearer believes something's not right with Rooney's situation at Old Trafford.

"Looking at it, things don't seem right," Shearer told the Sun.

"He has been left out of the team, shunted around (in different positions) and been subbed more than once.

"I would be wondering just where I stand. If he is not happy, he needs to move."

Rooney has been linked with a move away for quite a while, with Paris Saint-Germain recently admitting their admiration for the player.

Shearer said leaving Rooney, who has scored 16 goals this season despite the inconsistencies, out of the starting lineup in the Champions League game against Real Madrid showed he was no longer first choice.

"It is obvious he is not the No. 1 there anymore," Shearer added. "Robin van Persie is the automatic choice up front.

"Wayne is not even certain of being on the teamsheet, as was proved against Real Madrid at Old Trafford.

"It was a decision I didn't agree with and must have made Wayne wonder where he stands at United right now.

"He is still England's main hope yet he wasn't good enough for Manchester United on their biggest night of the season for what were described as 'tactical reasons.'"

Shearer believes Rooney being asked to play in different positions this season shows that Sir Alex Ferguson probably does not have the same faith in the player he had a couple of seasons ago.

"I have to ask myself if he had not scored for 10 games, like Robin van Persie recently, whether the manager would have persevered with him.

"I have always said that Rooney would be the best player on the pitch wherever he plays, bar in goal.

"Right now, that is being tested, too. He has gone from the main frontman, to the supporting role in behind Van Persie, to out wide and a deep-lying midfield role.

"You have to ask yourself whether this would happen to someone like Cristiano Ronaldo or Lionel Messi.

"People will say that he is not in their class. But three or four years ago he was being talked about in the same breath.

"He is 27 and these should be the best years of his career coming up but he is not at the level we all expected he would be.

"He has to sit down with his advisors in the summer and ask himself whether or not a move would be beneficial.

"He is already at a great club with a great manager but things just don't look rosy to me."