Paul Merson has claimed Pierre-Emerick Aubameyang would only join Man Utd out of greed rather than ambition.
The Arsenal captain could be on the move this summer with the Red Devils among the clubs interested in signing him.
Aubameyang has been stalling over penning a new deal at the Emirates as he waits to see whether Arsenal qualify for European football next season.
United look on course to do so, and could yet sneak into the Champions League.
But Merson feels a switch to United would be nothing more than a sideways step for Aubameyang.
"I don't think you can say Aubameyang would be going for ambition if he went to Manchester United," Merson told Sky Sports.
"He'd be going for the money because he's almost 31 and this would likely to be his last move.
"At the moment, you can't say you are going to go to Manchester United and get guaranteed trophies. You won't be able to guarantee United winning anything in the next two or three seasons. They are getting better but it's not ambitions, it's the money.
"If it was Manchester City or Liverpool, that would be different. You'd be thinking of course, he's ambitious and he wants to win things.
"I'm not saying United won't win things, but you can't assure me of it. I can assure you Man City or Liverpool will in the next few years."
Aubameyang's current deal runs out in 2021, but Arsenal could be forced to sell this summer out of fear of losing him for nothing next year.
Real Madrid, Barcelona and Inter Milan have also expressed an interest in the forward, and Merson feels if United can land Aubameyang, it would be a huge coup for the club.
"They [United] are crying out for someone who is going to score them 20 to 25 goals, and that's what Aubameyang can bring," Merson added.
"He gets you 25 goals without even breaking sweat. Add a [Jack] Grealish if they can get him and then you've got Bruno Fernandes as well playing in behind a striker, Manchester United will be a major force."
