In this Nov. 20, 2016, file photo, 49ers quarterback Colin Kaepernick (7) kneels next to outside linebacker Eli Harold (58) and safety Eric Reid, right rear, during the national anthem before a game. (Marcio Jose Sanchez/AP)

Shortly after San Francisco benched Colin Kaepernick a couple seasons ago, descriptions of Kaepernick as an aloof teammate surfaced. Teammates suggested to some reporters that they didn’t see him as a leader, despite being a quarterback. They struggled to connect with him.

During last season, as Kaepernick roiled the league and the country with a demonstrative pregame act, I heard he lived up to his reputation as a loner by telling some players who wanted to support him that he preferred to do his thing on his own.

It was a year ago this weekend, the opening of the 2016 NFL preseason, when Kaepernick first refused to stand at attention for the national anthem. It wasn’t until he made his remonstration during the anthem more distinct in subsequent games — by dropping to a knee, rather than sitting on the bench — that the rest of us took note. NFL Network reporter Steve Wyche spied Kaepernick kneeling and asked the quarterback what he was doing.

“I am not going to stand up to show pride in a flag for a country that oppresses black people and people of color,” Kaepernick told Wyche postgame. “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.”

It didn’t sound then as if Kaepernick intended for his righteous protest against the unchecked extrajudicial killing of black men in this country to be about him. But unfortunately, so it has been reduced.

A coalition under the banner “United We Stand Rally for Colin Kaepernick” announced it will hold a rally outside the league’s headquarters on Park Avenue on Aug. 23. A petition was posted late last month calling for a boycott of the NFL.

The efforts are born out of anger against the league and, more specially, its franchises, which collectively have barred their locker room doors to Kaepernick since he opted to become a free agent in the offseason. Lesser quarterbacks have been given contracts, including some who were coaxed out of retirement.

But Kaepernick, not yet 30 and just a few seasons removed from leading San Francisco to the Super Bowl, can’t get into a training camp. As I suggested five months ago in these pages, it is not surprising in a league that has drenched itself in patriotic and militaristic imagery and is run by owners who are mostly supportive of conservative politics, stakeholders find Kaepernick’s stridency repugnant.

However, it made me wonder whether Kaepernick’s strategy to be a soloist rather than a bandleader allowed his cause to get obfuscated. Indeed, we are no longer talking about the number of people felled by police, which is greater this year than at the same time last year when Kaepernick started his protest. And black men are still roughly 2.5 times more likely to be those victims than white Americans.

Without question, we the public, NFL fans and Kaepernick’s brethren should be concerned about Kaepernick’s inability to get a fair shake from a game that, since it rescinded its racial segregation agreement after World War II, touts its playing field as one ruled by meritocracy. Who among us would be comfortable working for an employer who would shun you because you voiced an opposing political opinion? Federal law offers no protection from employment discrimination based on politics, but states may provide such protection and many have done so, including some in which NFL teams reside.

It would seem an easy mantle for the NFL Players Association to pick up. But the union’s executive director, DeMaurice Smith, told me during a visit to his office this week that the 32 player representatives around the league haven’t called his office en masse demanding a grievance be filed or some other action taken on Kaepernick’s behalf as some in the public are demanding.

Smith said he hasn’t been informed that his membership, so willing to wear ribbons and patches approved by the league to remember recently deceased NFL icons or teammates, wants to wear black arm and ankle bands to indicate their displeasure with the league’s stance against Kaepernick. Instead, Smith said, his office is proceeding on Kaepernick’s behalf as the quarterback and his agents have preferred: alone. Truth is, other NFL players are tacitly supporting the league’s lockout of Kaepernick by doing nothing.

A number of observers have juxtaposed the political atmosphere of the NBA with that of the NFL, as the NFL’s cold shoulder to Kaepernick has become more evident since training camps opened this summer. The NBA, it has been argued, was more progressive and likely to embrace a Kaepernick in its midst. Look at the ouster of owner Donald Sterling, people pointed out. Look at the visual protest of Trayvon Martin’s murder led by LeBron James and Dwyane Wade.

But it isn’t just the leagues that are different; it is the players. The NBA protests were collective efforts, not individual. James’s voice was not alone. When it came to Sterling, the bigoted longtime owner of the Los Angeles Clippers, James’s words were echoed around the league. All of the Clippers, not just one, dumped their team jerseys in the middle of the court in a demonstration that they did not appreciate playing for someone with Sterling’s views about black men.

I remember being in the audience in college when civil rights icon Kwame Ture (formerly know as Stokely Carmichael) accepted an invitation from the black student group to speak. He asked us, quite angrily, whether we were organized. He implored us to act in concert, something historian Peniel Joseph underscores with rich detail in his 2016 biography, “Stokely: A Life,” recalling Carmichael building an independent black political party in rural Lowndes County, Ala., and helping to create the Freedom Summer Schools in Mississippi, and the Mississippi Freedom Democratic Party.

Kaepernick may have sat and kneeled in his protest mostly alone. But his cause, which we so rarely talk about these days, and his desire to work could use his brethren’s support now.

Kevin B. Blackistone, ESPN panelist and visiting professor at the Philip Merrill College of Journalism at the University of Maryland, writes sports commentary for the Post.