How does the author use foreshadowing in The Brave?

The Brave by Robert Lipsyte tells the story of Sonny, a half-white, half-Indian 17-year-old boy with a talent for boxing. Dissatisfied with his life on the Reservation, he heads off to the big city to join the army. Before he can sign up, he is targeted by drug traffickers who reel him into their cause. When he is busted, Sonny is faced with a choice regarding his future. He discovers that boxing goes far beyond the ring.This foreshadows the many fights that Robert must face in the narrative.