That is the verdict of Houston Dynamo's president Chris Canetti.
Wayne Rooney was linked with a move away from Manchester United in the January window.
MLS clubs and Chinese Super League outfits made big contract offers, but Rooney was persuaded to stay at Old Trafford until the end of the season.
The 31-year-old's future remains in limbo along with Zlatan Ibrahimovic, who has yet to sign a new deal with the Red Devils.
A move to the States is a realistic prospect for Rooney, who has seen his first-team chances fade under Jose Mourinho.
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Wayne Rooney faces an uncertain future at Manchester United
Wayne Rooney has fallen out of favour with Jose Mourinho
I think there’s been plenty of examples where it’s been proven that you can’t do that
And Canetti thinks Rooney will be in for a shock if he thinks the MLS is an easy ride.
"It still seems like he has something left in the tank," Canetti said.
"He would come over here and, I’m hoping, would be energised to play and wouldn’t be here just for the party or the money.
“It’s a tough league now. It used to be where some of these guys could come over here and think, ‘I’m just going to skate through’.
"I think there’s been plenty of examples where it’s been proven that you can’t do that.
"You need to be fit, you need to be focused and you need to take it seriously or you’re going to embarrass yourself."