During the third game of the 49ers preseason schedule, the world found out about Colin Kaepernick's silent protest against the national anthem. Since then, he's had people support him publicly and seen his jersey sales skyrocket.

On Tuesday, the first business day after Labor Day, and just 48 hours until the regular season kicks off, Kaepernick -- a backup quarterback for what many believe will be a very bad football team -- had the most popular jersey in the entire NFL.

Kap's No. 7 was the "top-selling" jersey on NFLShop.com.

Colin Kaepernick has the NFL's hottest-selling jersey. USATSI

Kaepernick surpassed Ezekiel Elliott of the Cowboys and Odell Beckham of the Giants. Carson Wentz of the Eagles, fresh off being named Philly's starter for Week 1, was hot on Kap's heels.

To put his popularity in context, Kaepernick has two different jerseys that are more popular than Tom Brady's first jersey. He has three jerseys more popular than the next 49ers player, Navorro Bowman.

It's fascinating to see how the NFL and the 49ers and everyone on the fringe of this protest treats the whole thing. Suffice to say, Kap is generating plenty of support for his stance against the American flag.