Kareem Abdul-Jabbar says Colin Kaepernick should be playing in the NFL

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Colin Kaepernick #7 and Eric Reid #35 of the San Francisco 49ers kneel in protest during the national anthem prior to playing the Los Angeles Rams in their NFL game at Levi’s Stadium on September 12, 2016 in Santa Clara, California.

The former star quarterback with the San Francisco 49ers has not played since becoming a free agent after the 2016 season. He filed a grievance alleging collusion by team owners in October 2017.

Kaepernick was the first player to kneel during “The Star Bangled Banner” in 2016, but several players followed suit. They were called out by critics as being disrespectful to the flag. Even President Donald Trump weighed in, urging NFL owners to fire the players who kneeled.

Abdul-Jabbar, a six-time NBA champion, has been a vocal supporter of the NFL protests. In a Washington Post op-ed in 2016 — when Kaepernick first gained attention for his protest — Abdul-Jabbar wrote, “We should admire those who risk personal gain in the service of promoting the values of their country.”

He also praised Nike for its “Just Do It” ad campaign last fall that featured Kaepernick. He told CNBC in September that people will someday compare Kaepernick to boxing great Muhammad Ali, who was suspended from boxing from 1967 to 1970 for refusing to fight in the Vietnam War and who also spoke out against racism and Islamophobia. “I think eventually he will be like Muhammad Ali in earning people’s respect when they finally think about what he was talking about and make some decisions based on fact.”

— CNBC’s Dan Mangan contributed to this report.