LONDON (AP) — Bryshon Nellum's doctors told him he might never run again.

Not on an elite level. And surely not in the Olympics.

Yet here he is in London, less than four years after gang members shot the former Southern California track star three times in the legs in a case of mistaken identity. Just a year ago he underwent his third and final operation to remove the last remnants of bullet fragments in his left hamstring.

Nellum will make his long-awaited Olympic debut Saturday in the preliminary heats of the 400 meters — the same event that features double-amputee Oscar Pistorius of South Africa. The man known as "Blade Runner" fought to compete alongside the other sprinters.

There's also the first big sprint showdown between the U.S. and Jamaica in the women's 100-meter final at Olympic Stadium.