Colin Kaepernick, Nate Boyer

After sitting for the national anthem three times during the exhibition season, 49ers quarterback Colin Kaepernick decided to modify his protest by kneeling with one leg. That change was the result of Kaepernick's conversation with Nate Boyer, a former Green Beret who played three preseason games as a long snapper for the Seahawks last year.

"We sort of came to a middle ground, where he would take a knee alongside his teammates," Boyer says on the latest edition of HBO's Real Sports. "Soldiers take a knee in front of a fallen brother's grave to show respect."

Boyer, who was a walk-on at Texas after serving six years in Iraq and Afghanistan, stood next to Kaepernick during the anthem before the 49ers' final exhibition game this season in San Diego.

"I was told I was a disgrace to the Green Beret," Boyer says. "That hurts. It really does. But then I also had a lot of people in the military say, 'I think you're on to something.'"

Boyer's story is part of a larger feature about the national anthem and sports. This episode premieres Tuesday at 10 p.m. ET/PT: