PHILADELPHIA — Weston McKennie is to many US soccer fans an example of a European success story after the 19-year-old's promising start at Bundesliga side Schalke 04.

And he’s certainly one of the most exciting prospects called in by Dave Sarachan to this week’s US national team camp ahead of Monday’s friendly vs. Bolivia (6:30 pm ET | FS1, UniMás, UDN).

But McKennie knows he wouldn’t have gotten to that point without the FC Dallas academy, where he spent seven years before turning down a Homegrown deal — as well as a scholarship offer from the University of Virginia — to test the professional waters in Germany.

“When people ask me if it was a hard decision to leave FC Dallas to go to Schalke, it was a hard decision for me,” McKennie told MLSsoccer.com before a US training session at Penn’s Rhodes Field on Friday. “One, it was hard because of loyalty reasons; I was there for seven years. And the other reason is because they had done so much for my development.

“For me, I see FC Dallas as one of the best academies in the country and it can also compete with some of the best academies around the world. They definitely helped me a lot and I have a lot to thank them for.”

McKennie — who scored a goal in his USMNT debut last November — is most thankful that the FCD youth coaches allowed him to play up, rather than keeping him in his own age group as soon as he joined the academy as an ultra-quick 10-year-old.

And it wasn’t long before he caught the eye of plenty of first-team players and coaches, including Walker Zimmerman, who’s five years older than McKennie and joined him at US camp this week.

McKennie in his FCD academy days | FC Dallas

“It’s pretty funny now seeing him all grown up and filling out his shirt a little more these days,” said Zimmerman, who played five years at FC Dallas before joining LAFC this season. “It was always fun to have him whenever he came out to train as an academy player. You could tell right away he had what it takes — the mentality, the physical qualities, his ability on the ball. You could see it, even at 16 and 17. So I’m proud of him, proud of the work he’s done, and I look forward to watching him continue to develop over the next few years.”

McKennie said he still follows FC Dallas, with a particular interest on players he climbed through the academy with, such as Reggie Cannon, Paxton Pomykal, Jesus Ferreira, Bryan Reynolds and Brandon Servania.

And he remains proud that his hometown club is one of the best in MLS at providing such a strong pipeline from the youth ranks to the first team.

“It’s always something that’s going to be in my heart, FC Dallas,” he said. “Who knows? Maybe one day in the future, I’ll find a way back there.”

For now though, McKennie is only focused on helping the USMNT move on from its World Cup qualifying failure and forge a new direction around a nucleus that includes him and of course, his good friend and fellow 19-year-old Christian Pulisic.

The two Bundesliga-based teenagers opened Friday’s training session juggling together, and they hope to line up in the same central midfield vs. Bolivia on Monday, offering weary American fans a glimpse toward a better future.

“I haven’t really played with him before so much,” McKennie said. “Back in [U.S. Soccer’s Bradenton] residency times, we were kind of split into two teams and I always played against him more than I played with him. Coming from the same league in Germany with me at Schalke and him at Dortmund, and us being friends since we were 13 years old, it’s kind of funny to see that now the national team has brought us back together and we can potentially be playing together.”