He will be a more mature and seasoned performer when that switch is made, with the Union set to benefit from precocious talent for some time yet. Are they doing enough to push Sullivan forward - with rivals such as the New York Red Bulls handing regular game time to teenagers Julian Hall, Adri Mehmeti and Matthew Dos Santos this season?
When that question was put to Adu, the former United States international - speaking exclusively to GOAL via https://casinostreamers.com/ - said: “I do think that he should have started more games than he has. At this point in time, anyways. I think he needs that experience. He needs to know or to learn how to be a regular starter for a team. For a professional team, is what I would say.
“He's obviously a regular starter when he plays with their youth team and also the youth national team and whatnot. But, it's different when you're playing against grown men who this is their job, who have kids, who have families to support. It's different. They worked their whole lives to get there. So, you need to learn as a young player how to be a regular starter. How to do whatever it takes to help the team win.
“Sometimes when you're a young player and you have a big name and they put you in, there will be games - there'll be a lot of games actually - where you have to play a sort of way that maybe you're not accustomed to because that's what's needed for the team to have the best chance in that particular game.”
Adu went on to say: “I do think that Philadelphia's being careful not to put too much on his plate right now. I do think that. But I think that there's a way you can do it. And Philly's right to be careful. I mean, it's a unique situation. But there is a way to do that.
“I think, in a 10-game span, maybe he gets four to six starts. And maybe you bring him off the bench and play half-an-hour or the last 20 minutes of the game etc. But he does need that experience. I think coming off the bench is a completely different sort of mentality than when you're a starter.”