Jurgen Klinsmann believes Christian Pulisic may not have ascended to the United States' national team had he developed in the MLS instead of Borussia Dortmund.

"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 college system could be a factor but American players tend to mature later than their peers 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."