Director Spike Lee's multipart documentary series for ESPN Films about former NFL quarterback Colin Kaepernick, who sparked a national debate when he protested racial injustice nearly a decade ago, will not be released, the filmmaker and ESPN said.

"ESPN, Colin Kaepernick and Spike Lee have collectively decided to no longer proceed with this project as a result of certain creative differences," ESPN said in a statement on Saturday.

"Despite not reaching finality, we appreciate all the hard work and collaboration that went into this film."