For several weeks in the spring, a high school junior named Casey Mittelstadt contemplated where he would play hockey the next year. He considered graduating high school early and enrolling at the University of Minnesota. He thought about playing for the Green Bay Gamblers of the United States Hockey League. Or he could continue to compete for Eden Prairie High School in suburban Minneapolis.

After agonizing over his options, Mittelstadt decided to play for the Gamblers from mid-September through mid-November and then return to Eden Prairie for one last season with his longtime friends.

“A lot of guys ask me, ‘What are you doing going back there?’” Mittelstadt, 18, said.

Elite American prospects like Mittelstadt, projected to be a first-round pick in June’s N.H.L. draft, usually do not play high school hockey, or they stop after their sophomore or junior year. Mittelstadt was the only high school player on the United States under-18 national team that won the bronze medal in the world championship in April. He had four goals and five assists in seven games.

Of the 42 players selected for the prestigious CCM/USA Hockey All-American Prospects Game in Philadelphia in September, Mittelstadt and Jack Rathbone, a junior at the Dexter School in Massachusetts, were the only two still competing for their high school teams.