PHILADELPHIA -- Seventeen-year-old Borussia Dortmund midfielder Christian Pulisic might not have received first-team minutes had he started his professional career in the United States rather than Germany, U.S. national team coach Jurgen Klinsmann said on Friday.

Pulisic made Klinsmann's squad for the ongoing Copa America Centenario after becoming a regular with Dortmund during the second half of the Bundesliga season. The Hershey, Pennsylvania native made nine appearances (four starts) in league play and 12 in all competitions for the German runners-up, scoring twice. He's the youngest player in Bundesliga history to have multiple goals in a season.

Yet Klinsmann, who helped Germany win the 1990 World Cup as a player and coached his country's squad to the semifinals in 2006, isn't sure the wiry teen would have gotten the same opportunities in his home country.

"We struggle traditionally with our 18-23-year-old generation," Klinsmann said a day before the U.S. was scheduled to meet Paraguay in their final group stage game.

"Who would have given Christian Pulisic a chance here [in MLS] as a 17-year-old to play?"

The comment could be interpreted as another subtle dig by Klinsmann directed toward Major League Soccer, which has objected to the coach's critiques in the past.

Teenagers have gotten plenty of opportunities in MLS, however. Freddy Adu is the most famous example, having been signed at 14 and playing 96 games for D.C. United and Real Salt Lake before his 18th birthday in mid-2007.

Landon Donovan couldn't get a sniff with Bayer Leverkusen's senior team before being loaned as an 18-year-old to the San Jose Earth Earthquakes in 2001. A year later, he scored two goals for the U.S. at the World Cup.

At 17, Christian Pulisic has made a splash with the United States and Borussia Dortmund. AP

More recently, U.S. defender Matt Miazga established himself as a starter at 19 for the New York Red Bulls last season, before moving to Premier League side Chelsea in January. And FC Dallas' Kellyn Acosta has been a starter since 2013, when he was 18.

Still, there are a variety of factors -- the college system being the most obvious -- promising American players tend to mature later than their counterparts around the world.

"Here, in the U.S. you call a younger player a rookie at the age of 22. At 22 in Europe, if you're not broken through yet, you're done. They move you down to third or fourth level.

"A lot of pieces fit into that question," Klinsmann continued. "But in general you have to give them more belief, you've got to give them more opportunities, you've got to let them make mistakes."

Klinsmann pointed to last year's Gold Cup, when young defenders Ventura Alvarado, John Brooks and DeAndre Yedlin struggled as the U.S. sputtered to a fourth-place finish.

Since then, Brooks and Yedlin have taken a huge step forward and are now automatic starters for Klinsmann's side. Alvarado, however, lost his place with Mexican behemoth Club America and didn't make Klinsmann's 23-man Copa roster.

"I think DeAndre [Yedlin] is an exception," Klinsmann said. "John Brooks fought his way through now, but we need more.

"We need to give them more support," he added. "They also have to help themselves more. But if you don't give younger players a chance, how do you want them to break through?"