AAron Ontiveroz, The Denver Post)
COMMERCE CITY — While most of his high school classmates were worried about such things as biology tests and who to ask to the homecoming dance, Zach Pfeffer was trying to balance morning and online classes while learning the ropes as a professional soccer player.
Pfeffer signed a homegrown contract at age 15 with the Philadelphia Union in December 2010, making him the fourth-youngest player in Major League Soccer history. His parents and friends cheered him on as he made his MLS debut against the Columbus Crew at age 16 in front of nearly 19,000 fans at PPL Park in September 2011.