Patrick Blake Leeper won 200m bronze at the Paralympics in London four years ago in the T43 category.
He finished behind Brazilian Alan Oliviera and South African Oscar Pistorius.
In the 400m T43 category, Leeper went one better and claimed a silver medal behind Pistorius in 2012.
He beat compatriot David Prince (right) to the silver medal.
On the eve of the Rio Paralympics, Leeper found out that the IPC had dashed his hopes of competing in the Games after he tested positive for a banned substance in 2015.
Leeper carries the Oakland Raiders flag in a break in play against the Denver Broncos in November 2014.