"Oh, he is being blackballed. That's a no-brainer. All you have to do is read the transactions every day, when you see the quarterbacks who are being hired. He's way better than any of them.
"But the NFL has a different fanbase than the NBA. The NBA is more urban, the NFL is more conservative, and I think a lot of NFL fans are truly angry at Kaepernick, and I think owners are worried what it's going to do to business."
Kaepernick and the Niners parted ways in March when he opted out of his contract, and he remains the most accomplished quarterback available on the free-agent market.
The signal-caller started a trend of protesting racial injustice during the national anthem during the 2016 preseason, and Kerr said that is why teams are hesitant to sign him: "If you are a general manager, you do have to worry about the circus that would erupt if you signed Kaepernick. That's not justifying not signing him, but it's understanding what you're getting into."
Per ESPN.com, Kaepernick filed a grievance against NFL owners two weeks ago, alleging they have colluded to prevent him from getting a job in the league.
The 2011 second-round pick out of Nevada went 1-10 as a starter for the 49ers last season but produced solid numbers.
He threw for 2,241 yards, 16 touchdowns and four interceptions while rushing for 468 yards and two scores.
Kaepernick also has playoff experience. The 29-year-old has posted a 4-2 record, and in 2012, he helped lead the 49ers franchise to Super Bowl XLVII—its first since 1994—where San Francisco lost 34-31 to the Baltimore Ravens.