San Francisco 49ers quarterback Colin Kaepernick made his preseason debut on Aug. 26 against the Green Bay Packers, but that turned out to be the second-biggest story for the 28-year-old.

NFLFemale.com's Jennifer Lee Chan captured a photo of Kaepernick sitting during the national anthem before the game kicked off, and Matt Barrows of the Sacramento Bee provided a zoomed-in image from Chan's picture:

Chargers fans loudly booed Kaepernick on Thursday when he entered Qualcomm Stadium for the 49ers' final preseason game, which also happened to be Military Appreciation Night, per Cam Inman of the Bay Area News Group.

Kaepernick sat during the anthem prior to Thursday's game as well, and was joined by 49ers safety Eric Reid who took a knee beside him, per Matt Maiocco of CSN Bay Area. Reid said after the game that it was Kaepernick's idea to take a knee to be more respectful, per Ebenezer Samuel of the New York Daily News.

Tim Kawakami of the Mercury News noted Kaepernick later applauded a tribute to the military on the stadium videoboard. Matt Maiocco of CSN added Kaepernick also stood for "God Bless America" and applauded the singing of Petty Officer 1st Class Steven Powell.

Kaepernick commented on Thursday night's decision and his plans for charity, per Inman:

On Aug. 27, NFL Media's Steve Wyche relayed Kaepernick's explanation for not standing:

I am not going to stand up to show pride in a flag for a country that oppresses black people and people of color. To me, this is bigger than football and it would be selfish on my part to look the other way. There are bodies in the street and people getting paid leave and getting away with murder. ...

This is not something that I am going to run by anybody. I am not looking for approval. I have to stand up for people that are oppressed. ... If they take football away, my endorsements from me, I know that I stood up for what is right.

On Aug. 28, Kaepernick said he is not taking this stand for himself, per Maiocco. Inman provided a series of videos capturing Kaepernick's interview in the locker room:

Mike Rosenberg of the Seattle Times provided more from Kaepernick:

The 49ers issued a statement about Kaepernick's choice not to partake in the pregame ceremony, via Wyche:

The national anthem is and always will be a special part of the pre-game ceremony. It is an opportunity to honor our country and reflect on the great liberties we are afforded as its citizens. In respecting such American principles as freedom of religion and freedom of expression, we recognize the right of an individual to choose [to] participate, or not, in our celebration of the national anthem.

On Aug. 30, Jason Cole of Bleacher Report reported the 49ers are worried about Kaepernick potentially being a distraction and divisive force in the locker room:

The NFL released a statement in response to the controversy on Aug. 27, per Ian Rapoport of NFL Network: "Players are encouraged but not required to stand during the playing of the national anthem."

On Aug. 29, the San Francisco Police Officers Association wrote a letter to the NFL asking for an apology, per Marianne Favro and Brendan Weber of NBC Bay Area:

"Not only does he show an incredible lack of knowledge regarding our profession and 'officer involved' shootings, but also shows a naivety and total lack of sensitivity toward police officers," SFPOA President Martin Halloran wrote in the letter. "Ironically it is those officers who on numerous occasions have protected Mr. Kaepernick."

"It takes a strong individual to stand up like that," 49ers receiver Torrey Smith said, per Eric Branch of the San Francisco Chronicle. "That's a right that we have."

Kaepernick has been using social media—notably retweets—to express anger and frustration with racial injustices.

Per Mike Florio of Pro Football Talk, Kaepernick on Aug. 25 retweeted an image of the American and Confederate flags with this caption: "The fact that you really believe that there is difference in these flags means that your [sic] ignoring history."

The post has since been deleted.

Kaepernick was 2-of-6 passing for 14 yards and added 18 yards on four carries in a 21-10 loss to the Packers. Niners head coach Chip Kelly has not said whether Kaepernick or Blaine Gabbert will be the team's starting quarterback for its regular-season opener against the Los Angeles Rams on Sept. 12.