King wrote, "I spent a long draft weekend with the Niners in California, and there are those in the building who think Kaepernick might actually rather do social justice work full-time than play quarterback."
King added: "I haven't talked to Kaepernick, so I have no idea what his gut is telling him about what to do with his life. But it's crazy that a quarterback who four years ago was coming off a Super Bowl appearance and looked to be a long-term answer has no team now and no hot NFL prospects that anyone can see."
Kaepernick, 29, spent the past six seasons with the Niners, leading the team to the Super Bowl in the 2012 season and the NFC Championship Game the following year. His play has fallen off since then, however, and the Niners haven't been back to the postseason.
In 12 games in 2016, Kaepernick threw for 2,241 yards, 16 touchdowns and four interceptions while also rushing for 468 yards and two scores. The team went just 2-10 in games he appeared in, however.
Kaepernick also became a national story after deciding to take a knee during the national anthem before games in a protest of police brutality and the unfair treatment of minorities in the United States. Other players around the league joined in the practice, putting Kaepernick at the epicenter of a controversy that lasted through the season.
With the quarterback still unsigned, many have suggested that his free-agent status is due to his political stances more than his play on the field. Other theories, like Kaepernick adopting a vegan diet, have also been floated to explain his unsigned status.
In the interim, Kaepernick has been living in New York City and doing charity and activism work, per King, who noted that Kaepernick donated "100 men's suits to a parole office in Queens, so recipients, recently out of prison, would look more presentable when going on job interviews."