SAN DIEGO (KRON)—San Francisco 49ers quarterback Colin Kaepernick and safety Eric Reid were kneeling down during the national anthem Thursday night in San Diego.

It happened before the 49ers played the San Diego Chargers at Qualcomm Stadium at 7 p.m.

Football fans booed Kaepernick as he was walking onto the field and when he dropped down on one knee during the national anthem.

This particular preseason game is called “Salute to the Military,” which the Chargers have every year.

Leo Uzcategui, a 20-year Navy veteran who served in Afghanistan, brought an American flag to the game.

Uzcategui spoke of how much he disapproves of Kaepernick refusing to stand.

“This is America all right,” Uzcategui said. “Men and women bleed for this. I’ve seen it first-hand and for someone to do that who gets paid millions of dollars, it’s ridiculous.”

Kaepernick’s protest against standing for the national anthem has caused much controversy across the country.

His protest first came to light when he did not stand during the anthem at a preseason game against the Green Bay Packers on Friday.