Denver Broncos linebacker Brandon Marshall, who played with Kaepernick at the University of Nevada, told TMZ Sports the former San Francisco 49ers star "still wants to play football" and "still loves the game very, very much."
After going unsigned as a free agent last year, Kaepernick filed a grievance in October 2017 arguing the NFL and its 32 team owners colluded to keep him out of the league due to his social and political activism.
Per Charles Robinson of Yahoo Sports, arbitrator Stephen Burbank refused the NFL's request for a dismissal of Kaepernick's case and it will move to trial.
Kaepernick grabbed headlines this week when he was among the athletes included in Nike's celebration of the 30th anniversary of its "Just Do It" campaign. He is featured in an ad campaign with the slogan: "Believe in something. Even if it means sacrificing everything."
The 49ers drafted Kaepernick in the second round out of Nevada in 2011. He led the team to an appearance in Super Bowl XLVII and threw 72 touchdowns in 69 games.
Kaepernick's last appearance in an NFL game was on January 1, 2017 against the Seattle Seahawks.