NFL spokesman Brian McCarthy provided some information about the league's random drug testing policy on Twitter.
"Each week during the season, 10 players per club will be tested," McCarthy wrote. "By means of a computer program, the policy's jointly appointed Independent Administrator randomly selects before the game players to be tested."
The league's response comes after Reid commented on being randomly selected for a drug test after the Panthers' 52-21 loss to the Pittsburgh Steelers on Thursday. He was ejected from the game in the third quarter for a shoulder-to-helmet hit on Ben Roethlisberger.
"This is like the fifth time since I've been here," Reid said, via Marcel Louis-Jacques of the Charlotte Observer. "They're not going to catch me on anything."
Reid filed a collusion lawsuit against the NFL after he went unsigned during free agency. He signed a one-year deal with the Panthers in September and has started each of the past six games.