Freddy Adu has obligations to his MLS Squad DC United...
He was born in Ghana, Africa so he would likely play with one of the African teams if this was the case.
Adu is being groomed even still to play in Europe, this MLS is one of the leagues that were willing to take part in him at such a young age, this is nothing but a good learning experience for him. Freddy Adu will be playing with a large European team sometime within the next 2 years. Manchester United were rumored to have ties to him but nothing concrete made there yet.
I have Adu on my Manchester United FIFA 2005 team
His stay in the US won't last that long I"m sure.