Gyllenhaal plays the role of Billy 'The Great' Hope, a left-handed prizefighter who wins a title but suffers a tragedy soon after and must put his life back together, reported the Wrap.
Whitaker is nearing a deal to play the other lead of Titus 'Tick' Willis, a former fighter who was forced to retire after losing an eye and now trains amateur fighters.
Whitaker, who won an Oscar for 'The Last King of Scotland', was recently seen in 'The Butler'.