Colin Kaepernick is still busting his ass to get back in the NFL ... the ex-49ers superstar just posted a workout video -- and it's INTENSE.
The video shows Kap getting after it in the weight room -- there's push-ups, bench presses, rows, tricep pull-downs and dips ... the guy is CLEARLY still in fantastic shape.
And, with the NFL season starting ... it's obvious Kaepernick wants people to know that despite a settlement in his collusion case with the NFL -- he's still working to make a roster.
In fact, the video starts with the number 889 -- the amount of days Kaepernick says he has been "denied" a job in the league.
Of course, the 31-year-old last played in the NFL in 2016 when he was San Francisco's quarterback ... but he claims controversial kneeling protests during the national anthem forced him to be blackballed from the league.
By the way, Houston Texans backup quarterback AJ McCarron suffered a thumb injury this week and the team is reportedly looking to sign a quarterback for camp ASAP.