Colin Kaepernick hasn't played in an NFL game since Jan. 1, 2017, but he hasn't stopped preparing to play in more. 

Despite not being on a roster since he opted out of his contract with the 49ers in March of 2017 after San Francisco's new front office said Kaepernick would be released if he didn't, the quarterback has kept active in the gym. Kaepernick tweeted a video Wednesday saying he has been training at 5 a.m. "five days a week three years."

If Kaepernick remains unsigned at the start of the NFL regular season on Sept. 5, then 2019 will mark the beginning of a third consecutive campaign in which he was not on a team. During his final season with the 49ers in 2016, Kaepernick first sat, then kneeled, during the playing of the national anthem to protest racial inequality and police brutality. Kaepernick then became a political talking point, receiving criticism for disrespecting the American flag and veterans -- even though the idea of kneeling came from a conversation with former Green Beret Nate Boyer. 

Kaepernick filed a collusion grievance against the NFL after going unsigned when he opted out of his deal with the 49ers, and settled with the NFL earlier this year. While Kaepernick remained out of the league, a steady drumbeat of doubts followed.

 

[RELATED: 49ers' Verrett, Bosa undergoing MRIs for ankle injuries]

Some -- such as NFL commissioner Roger Goodell -- have suggested that Kaepernick would've been signed if teams thought he could help, ignoring the revolving door of statistically-inferior quarterbacks at the bottom of teams' depth charts. Others insisted that Kaepernick, who has said before that he still wants to play football, didn't want to keep playing football. He was criticized for reportedly turning down a $20 million contract with the Alliance of American Football, which missed part of its payroll after one week and folded after eight. 

Plenty of people have already made up their mind on Kaepernick, and anything shy of him wearing an NFL uniform won't silence his critics and those who disagree with his activism. Wearing such a uniform, of course, isn't his call to make alone.