Carolina Panthers safety Eric Reid, the first player to kneel alongside Colin Kaepernick, has questioned the frequency of his random drug tests.

Reid joined the Panthers earlier this season and, excluding the mandatory test when he signed for the team, he has been given a random drugs test six times in 11 weeks. When he was notified of his random test after Monday’s game against the New Orleans Saints he posted a picture of the notice on Twitter alongside the quote: “Number 7... ‘Random’”.

Jonathan Jones (@jjones9) Panthers S Eric Reid on his seventh random drug test this year and whether it will be part of his grievance case against the league pic.twitter.com/w0Heqzj264

“I’ve been here 11 weeks, I’ve been drug-tested seven times,” Reid told reporters after the game. “That has to be statistically impossible. I’m not a mathematician, but there’s no way that’s random.”

'A neo-colonialist sellout': Kaepernick fractures spill on to the field Read more

Reid’s tests are not statistically impossible but they are highly improbable. According to Yahoo Sports, the chances of Reid being chosen six times in 11 weeks for random tests is 0.17%. Ten of the 72 eligible players on the Panthers roster are selected by computer for tests each week.

Reid was the first NFL player to join Kaepernick’s protest against racial injustice in the United States. In May, Reid filed a collusion grievance against the NFL alleging he had been kept out of the league due to his political stance. He eventually signed for the Panthers in September after the season had started.

Reid’s deal with the San Francisco 49ers expired in March, and on playing ability alone he would have been expected to have found a new team quickly: in 2013 he was named to the Pro Bowl as a rookie after being drafted in the first round and has had a solid career since. Reid believed that, like Kaepernick, he was unemployed due to his political views. “The notion that I can be a great signing for your team for cheap, not because of my skill set but because I’ve protested systemic oppression, is ludicrous. If you think [it] is, then your mindset is part of the problem too,” Reid wrote on Twitter earlier this year.

Reid has continued to kneel during the anthem since his return to the NFL.