Eric Reid said former San Francisco 49ers quarterback Colin Kaepernick's NFL workout "feels like a PR stunt".
NFL teams have been invited to attend a private workout held for Kaepernick on Saturday as the outcast eyes a return to the league.
Kaepernick has been out of the NFL since the end of the 2016 season, during which the ex-49ers QB attracted controversy by kneeling for the United States national anthem in protest against racial injustice and police brutality.
He filed a grievance against the NFL in 2017, accusing owners of colluding to keep him out of a job. Kaepernick settled that grievance in February.
Reid kneeled alongside Kaepernick in 2016 and also filed a grievance against the league, but he was signed by the Carolina Panthers in 2018.
Asked about the workout, Panthers safety Reid told reporters on Wednesday: "At this point I'll believe it when I see it. At this point it feels like a PR stunt, again it being on a Saturday.
"What decision-makers are going to be able to attend the workout? Other strange thing is I saw reports that teams are interested in Colin, but they reached out to the league about it. That's strange, so we'll see what happens.
"It's disingenuous. They want the appearance of giving Colin a chance, but they give him two hours' notice and tell him it has to be on a Saturday when they know decision-makers are traveling. So is this real? We'll see."
While Reid and Kaepernick are sceptical about the workout, the 32-year-old quarterback is ready for his audition, which is reportedly set to be attended by representatives from the Miami Dolphins, Detroit Lions, Atlanta Falcons, Tampa Bay Buccaneers, Denver Broncos, Washington Redskins, Dallas Cowboys and Arizona Cardinals.
Reid added: "I spoke to him [Kaepernick] last night. He had the same concerns that I just mentioned about why it's on Saturday.
"But he's ready, he's been training like I've been telling y'all ever since I got here. For three years now he's been training so he's ready."
"He has a rocket for an arm," Reid continued. "He's tall [6-foot-4], so he can see over the pocket. And he's mobile. He's [Baltimore Ravens quarterback] Lamar Jackson before Lamar Jackson. And he can still throw the ball.
"He's in the prime of his career. He still has a cannon for an arm. He can still run. Too late for his career? No."