"When you go back, tell your owners to stop being scared," Kaepernick told team scouts, according to Jourdan Rodrigue of The Athletic.
The owners weren't the only ones Kaepernick called out, per Jay Busbee of Yahoo Sports: "We're waiting for the owners and commissioner [Roger] Goodell to stop running from the truth."
Kaepernick has not been on an NFL roster since he opted out of his contract with San Francisco following the 2016 NFL season, a decision that came after the 49ers made it clear they would release him otherwise.
It was in 2016 that Kaepernick became the first NFL player to actively protest against social injustice by taking a knee during the national anthem. As he remained unsigned, he filed a grievance against the NFL in October 2017, saying the league colluded against him.
The case was settled in February under confidential terms.
The 32-year-old passer's representatives issued a statement last month that said the six-year NFL veteran had received "little to no response" from teams regarding a potential opportunity.
On Tuesday, the NFL invited all 32 teams to a workout in Atlanta, with Kaepernick scheduled to take part in both on-field work and an interview. Video footage from both portions of the showcase was to be delivered to each club.
Kaepernick called an audible Saturday by changing the location of the workout from the Atlanta Falcons' facility to an Atlanta-area high school, a move that allowed media to be in attendance. The NFL said it was "disappointed" with that decision, noting 25 of the 32 teams had shown up for the workout at the original location.
Earlier this week, ESPN's Stephen A. Smith reported on First Take that two teams have expressed interest in Kaepernick, though he said there were "at least 10 owners, if not more, that want nothing to do with him":
Kaepernick now must wait to see if Saturday's workout will lead to any opportunities to continue his NFL career.