Colin Kaepernick is a 32-year-old quarterback with 72 career touchdown passes, 13 rushing touchdowns, 30 interceptions and a Super Bowl start. But it has been almost three seasons since he played in the NFL, and during that time he has been more of a symbol and a lightning rod than a football player.

Now the league has organized a pro-day-style workout for Kaepernick in Atlanta on Saturday and invited all 32 teams to attend. This raises a lot of questions. How did we get here? What happens next? We thought we'd try to answer all of the questions for you:

Let's rewind: What happened with Kaepernick, and why is he out of the NFL?

Kaepernick ignited controversy in 2016 when he began sitting (and later kneeling) during the pregame playing of the national anthem in protest of police brutality and racial inequality. He finished that season as the San Francisco 49ers' starter, but he opted out of his contract at the end of 2016 after the team made it clear to him that it planned to release him.

Since that time, he has not played in the league and no team has had him in for a workout. (Seattle had him in for a visit but did not work him out or offer him a contract.) In October 2017, Kaepernick filed a grievance against the NFL alleging collusion by team owners to keep him out of the league. This past January, Kaepernick and the league reached a settlement.

Wait. He wasn't the only one who protested, right?

Right. Other players joined Kaepernick in protesting social injustice during the anthem. Former 49ers safety Eric Reid actually filed his own collusion grievance after it took him a long time to find a job in free agency during the 2018 offseason. (Reid eventually signed with the Panthers and has continued to kneel during the playing of the anthem.)

Michael Bennett remained in the locker room during the anthem earlier this season while with the Patriots, though he has been standing for the anthem since being traded to the Cowboys. Players such as Malcolm Jenkins in Philadelphia and Kenny Stills in Miami and now Houston have engaged in their own forms of protest.

The issue crescendoed early in 2017 following critical comments from President Donald Trump, and NFL owners passed a new rule governing anthem behavior in May 2018. But after discussions between the league and the NFL Players Association, that rule was never enforced, and the intensity of the issue has largely died down since.

What has Kaepernick been doing the past three years?

Other than suing the league for collusion and continuing his community work, which has included donating more than $1 million to charities working on behalf of social justice, Kaepernick has, according to his representatives Jeff Nalley and Jasmine Windham, been working out in an effort to stay ready for when and if he gets a call from an NFL team. Which he has not yet received.

Why is this workout happening now?

Sources familiar with the league's thinking say there are two reasons: First, a little over a month ago, Kaepernick's representatives put out a lengthy statement to address what they described as "false narratives" surrounding Kaepernick's situation and to assert that he still wanted to play.

Second, several teams have been in contact with the league office to ask about Kaepernick's status, and the league has grown tired of telling teams they're free to find out for themselves. Potentially interested teams haven't wanted to bring in Kaepernick for visits or workouts the way they routinely do on Tuesdays during the season, so the league is organizing Saturday's workout so that interested teams can check him out en masse.

Is this a part of his settlement with the league on the collusion grievance?

Multiple sources say no, that the league is not required to hold this workout as part of any settlement.

How long has the NFL been planning this?

Unclear. One source Wednesday said the league had been in conversation with Kaepernick and his representatives about a workout like this over the past few months. But another source said there had been no contact between the league and Kaepernick's reps in more than a year.

Did Kaepernick know this was coming?

No, he did not. The NFL reached out to Kaepernick's agent, Nalley, around 10 a.m. ET Tuesday and told Nalley the league would be circulating a memo to all 32 teams at 4 p.m. ET announcing the plans for the workout. That was the first Kaepernick heard of this, and he and Nalley responded with a few requests, most of which were denied.

They asked if it could be held on a Tuesday, when most in-season player workouts are conducted. They asked if the workout could be pushed back later than this week to allow Kaepernick more time to prepare. The league said no to both of those requests and told Kaepernick it would provide him with a list of the team personnel who were planning to attend the workout. (ESPN's Adam Schefter reported Wednesday evening that the NFL has reversed its decision to provide the list.)

Kaepernick tweeted Tuesday that he looked forward to seeing head coaches and general managers at the workout -- an indication of his own skepticism about how seriously teams would take the whole thing.

So why is it on a Saturday, then?

The NFL wanted to have the workout at an NFL team facility, and it didn't think a team would want to open its facility to the other 31 teams on a Tuesday or any other day when it would be going through its normal game preparation. The league determined that it could use the Falcons' facility on Saturday afternoon, after the Falcons had left for their Sunday game in Carolina.

Who's going to be at the workout?

The workout is being organized by Jeff Foster, the president of NFL scouting, who among other things is responsible for selecting college players for the annual NFL combine. The on-field workouts will be conducted by former NFL coaches.

As for which teams and who specifically from those teams will be there ... Kaepernick and his representatives are still waiting to see that list. When and if they get one, it would be surprising if most or even all of the league's 32 teams aren't represented, since there's no harm in sending someone to at least take a look. But those who show up are more likely to be scouts or personnel executives than the GMs and head coaches Kaepernick tweeted he's eager to see.

It's extremely unlikely that any head coach or GM whose team plays on Sunday or Monday will make the trip. It's possible that the Steelers and Browns, who play Thursday night, could send their coaches or GMs, or that higher-ranking officials from the four teams that are on bye this week -- Tennessee, Green Bay, Seattle and the Giants --- could go if they were interested. But that's just speculation. I have no specific information on those teams' plans in this matter.

What are the chances he signs and plays this season?

Pretty remote, and this is an important thing for people to understand. The idea that a team would sign Kaepernick now and expect him to start games this season is incredibly far-fetched.

First of all, as we've mentioned, he hasn't played in three years. Second, you just don't see teams pick up quarterbacks during the season for the purpose of starting games for them right away. Yes, Jimmy Garoppolo started the final five games of the 2017 season for the 49ers after they picked him up in a late-October trade, but that was neither the Niners' plan nor their reason for acquiring him. The Niners got Garoppolo to start for them in 2018 and beyond. The main reason he started so soon was because C.J. Beathard got hurt and the Niners were well out of the playoff race.

You don't generally see a team pick up a quarterback from outside the organization, teach him the offensive system in a week or two and ask him to step in and save the season. Translation: If you're a fan of the Bears imagining Kaepernick replacing Mitchell Trubisky by Thanksgiving and leading you to the playoffs, you're in a fantasy world.

Any team looking at Kaepernick this weekend would be doing so with the thought of adding him to its overall quarterback picture for next season and beyond. It's possible a team could sign him and get him into its building to prepare him for a 2020 role. It's also possible no team signs him until the offseason. And, as the past three years have shown us, it's obviously possible no one signs him at all.

What would it cost to sign him?

It couldn't possibly be much at this point. During that 2017 offseason, sources said Kaepernick was looking for a low-end starter or high-end backup salary, which would have been justified given where he was in his career at that point.

Of course, that information turned out to be irrelevant, since no team ever actually found out what he was looking for because they didn't ask. At this point, it's hard to imagine he could ask for much more than a veterans minimum deal with a bunch of incentives tied to playing time and performance. Teams that go to the workout might have a chance to ask Kaepernick in person, since part of the plan is for him to submit to an interview, a video of which will then be circulated to all 32 teams.

Is he good enough to help someone?

Of course he is. You can argue whether Kaepernick is good enough to open the 2020 season as a starting quarterback. But you can't argue that he's not good enough to be on a team's roster. He has been for three years. According to ESPN Stats & Information research, Kaepernick's 2016 numbers with the 49ers show that he was better that season in Total QBR (49.4) and TD-INT ratio (4.0) than the average NFL backup (42.5, 1.6) has been this season.

Kaepernick as a player was not without his flaws, and there's little doubt he could have benefited from some NFL coaching during his exile. But his talent alone should have landed him a spot on someone's QB depth chart long before now.

If he does get signed, will Kaepernick continue to protest during the anthem?

In March 2017, ESPN's Adam Schefter reported that Kaepernick planned to stand for the national anthem that season. Of course, he never got the chance and hasn't commented on it publicly.

So is this all just a publicity stunt?

That has been suggested by some close to Kaepernick, including Panthers safety Eric Reid. But it doesn't seem likely in the strictest sense, since it's hard to see how this offers much of a potential public-relations boost for the NFL. The league is having a good year. TV ratings are up. Interest in young stars such as Patrick Mahomes and Lamar Jackson is high. This past week featured exciting, down-to-the-wire prime-time games between high-profile teams. The anthem protests haven't been at the forefront of any coverage or discussion about the league in quite a while, and there's little doubt the NFL prefers it that way.

Those who were angered by Kaepernick's stance aren't likely to appreciate that this issue has come up again. Those who disdain the league for unfairly keeping Kaepernick unemployed aren't likely to change their position because of this workout. If anything, this injects the potential for negative PR at a time when the league is doing all right.

Now, all of that said, I'm not going to sit here and tell you that the NFL or any other multibillion-dollar corporation is acting purely out of the goodness of its heart and without any regard for its own self-interest. So if you want to believe this is an effort to head off questions that might come up from the union during collective bargaining agreement talks or from TV networks during negotiations of new deals or to ward off potential future lawsuits, go right ahead. You might be right on any or all of those fronts. But from a PR standpoint, it's hard to see how this does anything for the league.