Temperatures were hot during the late afternoon practice at the Virginia school, but a cause of death was not yet determined.
Hirten had transferred from Hobart, another Division III school, last year. He starred at Staples High School in Westport, Conn.
"Preston epitomized Staples soccer," said Staples head coach Dan Woog. "Anyone who watched him play - who saw his combination of speed, skill, and above all determination - knew he loved the game, and loved being on the field with his friends."
Hirten is survived by his parents, Marc and Lisa Hirten, and two sisters Ella and Justine.
A memorial service will be held this Saturday at the Unitarian Church, 10 Lyons Plains Road, Westport. The service begins at 2 p.m.
The family also notes that, in lieu of flowers, contributions may be made to the Preston Hirten Memorial Scholarship, being organized by the Westport Soccer Association. The address is: PO Box 2561, Westport, CT 06880.