The England international has been linked with a move away from Old Trafford at times this season after reported disputes with manager Sir Alex Ferguson.
However, Hargreaves is confident that the striker can become one of United's best ever players should he opt to stay with the Red Devils.
"Wayne Rooney is one of the best players in the world," Hargreaves told talkSPORT. "He provides so much to the team. I just don't know where he'd go. I don't see the point.
"If he was German I'd say he could go to Bayern Munich and if he was Spanish it would be Real Madrid or Barcelona, but he's not. He's virtually a local lad. He identifies with the Manchester United fan base. It's a massive club with great players and management.
"He can end up becoming one of the best players in Manchester United's history so I don't see the point in him going anywhere else."
Hargreaves won the Premier League and Champions League during his time at United.