San Francisco 49ers quarterback Colin Kaepernick continued his preseason protest by taking a knee during the national anthem before his team's game against the San Diego Chargers Thursday night.

His invited guest, a former Green Beret, stood tall.

Nate Boyer, whose open letter to Kaepernick at ArmyTimes.com included his desire to hear the quarterback out, got his wish before the game. He spoke with Kaepernick for about 90 minutes, according to Jay Glazer, longtime Fox NFL reporter and founder of Merging Vets and Players, a charity in which Boyer is an active member.

Boyer labeled it a "good talk" in a Twitter post featuring a photo of the two men.

Boyer was invited onto the sidelines by the quarterback and the 49ers, Glazer reported. The former staff sergeant, who was in camp with the Seattle Seahawks as a long snapper before being released prior to the 2015 regular season, stood with his hand over his heart during the anthem. Kaepernick and teammate Eric Reed took a knee.

The gesture came during Salute to the Military night at San Diego's Qualcomm Stadium. Service members in uniform lined the field during pregame festivities, and at least one veteran besides Boyer made his thoughts clear to Kaepernick before kickoff.

When the quarterback left the field following pregame warmups, he was greeted with profanity and obscene gestures from Leo Uzcategui, a 20-year Navy veteran in a military-green Chargers jersey with quarterback Philip Rivers' No. 17 in camouflage numbering.

"I was in the Navy and I saw men and women bleed and die for this flag," Uzcategui said. "If he wants to do something, go to some outreach program where he can do some good. And I get it, his First Amendment right. But you don't sit during the presenting of the colors, and you don't sit during the national anthem. That is not the way to do it."

In Oakland, Seahawks cornerback Jeremy Lane also sat on the bench behind his standing teammates as the national anthem was performed before Seattle's game against the Raiders.

Kaepernick has said he doesn't intend his stance to be a criticism of the military, claiming he has "great respect for the men and women that have fought for this country."

Kaepernick's social activism, which only emerged publicly in recent weeks, also included support for the Black Lives Matter movement through social media.

While negative reaction to the quarterback has been strong, Kaepernick also has been widely praised for his commitment to his stance. Veterans and military members tweeted their support for Kaepernick in recent days under the hashtag #VeteransForKaepernick.

Jim Brown voiced support for Kaepernick while disagreeing with his method of protest. Kareem Abdul-Jabbar called Kaepernick's decision "highly patriotic" while encouraging him to take further steps to build dialogue between law enforcement and blacks.

Amid the uproar of his emerging social activism, Kaepernick is still trying to win a job with the 49ers less than four years after leading them to the Super Bowl. The quarterback lost the starting job last season, and he hasn't separated himself from Blaine Gabbert this summer under new coach Chip Kelly.