Klinsmann was not made available to the news media after the national team practice Thursday because, a spokesman said, Klinsmann did not want to speak about Bradley until the deal was completed. The U.S. Soccer president, Sunil Gulati, also declined to comment.

But Klinsmann made his views clear with Dempsey.

“We all hope that, by going back to M.L.S., his own level is not dropping because he is going from the Premier League, one of the best in the world, into a league which is trying to improve every year,” Klinsmann told ESPN in August. “His job will be to keep his level the highest possible. My job is to help push him to that level and, when I am not happy, to tell him to his face."

Now, at 26, in the prime of his career and with a World Cup at hand, Bradley is returning to a league that is improving, but also to an environment in which the challenges for the best players — on the practice field and in games — must come from within.

Bradley left home for a soccer academy in Florida at 15 and turned pro at 16. By the time his high school class had graduated, he was headed to the Netherlands. He went on to play in Germany, England and Italy.

In some ways, Bradley is the antithesis of Landon Donovan, considered best American player of his generation. No player has endured more criticism for staying in M.L.S. than Donovan.

When he twice returned home from unfulfilling stints in Germany, and twice re-signed with the Galaxy rather than return to Europe to test himself in the world’s best leagues, the criticism was withering. He was not motivated. He was afraid. His talent was being squandered.