Christian Pulisic has a £58 million ($77m) move to Chelsea in place, but former United States international Landon Donovan admits to being “a little worried” at how his fellow countryman will get on at Stamford Bridge.
The Blues moved to ensure that they would be the ones to acquire the potential of the 20-year-old playmaker when fending off rival interest in January.
With the Premier League club now facing the threat of a two-window transfer ban, having been sanctioned by FIFA, their early approach for Pulisic has taken on even greater importance.
He told ESPN: "Candidly, I am a little worried and I think American fans should be a little bit. I understand the situation at Dortmund now; they are not going to play a player who is leaving in six months.
"The beauty of the situation with Christian is that he, by all accounts and from what I have seen, has a really good head on his shoulders, likes to compete and is oozing with talent."
Pulisic has made only 13 appearances for Dortmund this season and is set to form part of a star-studded squad when he arrives at Chelsea.
Donovan added: "From that standpoint it should be fine but what happens if you go to Chelsea, who fortunately for him have a two-window transfer ban, but have a bunch of other talented players and he doesn't get a chance to play.
"He is now either 20 or approaching 20 and needs to be playing games so that could be concerning.
"It is hard to turn down the allure of going to somewhere like Chelsea but it's the same argument I've made since I was 20 years old, when people ridiculed me for leaving [Bundesliga side Bayer] Leverkusen, if you are not playing games at that age, you are getting worse."
If Pulisic is given regular minutes by Chelsea and awarded time in which to adjust to demands of life in the Premier League, then Donovan believes he will be just fine.
"I just hope that he gets a fair opportunity to play," added a man with 157 international caps to his name.
"You just never know with a manager. When you're playing in America, for a club in America, you get the benefit of the doubt. But when you're playing somewhere else, they don't care if you're from America or Ghana or Argentina, they are going to play who they think should play.
"So, he's got to prove he belongs there, which I'm hoping and guessing he will do, but it's going to be difficult. That's a club that's full of quality attacking players."