Mike McCarn/Associated Press

Carolina Panthers safety Eric Reid is unhappy with the NFL after receiving a fine for what he called a legal hit during Monday's 12-9 loss to the New Orleans Saints.

Reid tweeted he was fined $20,054 on a legal play that wasn't flagged for a penalty, noting he was "adding it to the file."

Reid has had a contentious relationship with the NFL since the offseason. He filed a collusion grievance against the league in May after going unsigned as a free agent during the offseason.

Since signing with the Panthers on Sept. 27, the NFL has drug tested Reid seven different times:

Even Panthers head coach Ron Rivera seemed to imply that Reid's random drug testing was excessive.

"If my name came up that many times I would buy a lottery ticket," Rivera told reporterson Thursday.

Reid, along with former San Francisco 49ers teammate Colin Kaepernick, led the movement of players protesting during the national anthem in 2016. The 27-year-old has continued to take a knee prior to games since joining the Panthers.