Seattle Seahawks cornerback Richard Sherman has accused the NFL of trying to take the fun out of professional football, and suggested that TV ratings will continue to decline if the league continues on a quest to turn players into “robots”.

Sherman, a Stanford grad and one of the NFL’s most articulate speakers, wrote in an amusing yet acerbic piece in the Players’ Tribune on Thursday that the NFL is guilty of inconsistency and hypocrisy when it comes to punishing players for excessive celebrations. He also said that Roger Goodell, the commissioner, has too much power, and needs his authority challenged.

Sherman wrote: “If the NFL had its way, we would all be robots. We would all be perfect human beings off the field so that the league would never have to deal with another PR nightmare and everybody would smile and nod and hand the ball over to the official after a touchdown or a big play.

“We play a game,” he continued. “Part of the joy of watching that game is seeing the emotion on display. Seeing the passion. If guys didn’t play with passion and just went out there and went through the motions, I think people would stop watching.”

Sherman pointed out the hypocrisy of the NFL in punishing excessive touchdown celebrations. In recent weeks, Antonio Brown and Josh Norman have been fined for unsportsmanlike conduct, and Sherman said the punishments from the league were absurd.

“Antonio Brown can’t twerk after a touchdown because it’s sexually suggestive,” he wrote. “But every Sunday, on most sidelines, there are rows of cheerleaders doing the same types of moves to entertain the crowd. The NFL doesn’t want players to do anything that might set a bad example for the kids in its audience – such as showboat, or celebrate excessively – yet it features beer ads in all of its stadiums and in almost every commercial break. Josh Norman can’t shoot an imaginary bow and arrow after a big pick because the NFL says that it depicts a violent act. Meanwhile, the name of the team he plays for depicts Native Americans in a way that many people consider offensive.”

Sherman also said that the league failed in the Josh Brown domestic violence case, because it has no clear policy on dealing with contentious issues. Brown, the Giants kicker, was suspended for one game for hitting his then wife Kelly, despite the NFL claiming after the Ray Rice case that any player found guilty of domestic violence would be given a six-game ban. He said that led to a lack of trust among players.

Sherman wrote: “The league says that there is no place for domestic violence in the NFL. Its actions in the most recent cases, however, simply haven’t reflected that. This is just another reason why players don’t have a lot of trust in the league. The league says one thing — like how seriously it takes domestic violence — but when it comes time to act, it does another.”

Sherman said the league was “reaping what it has sown”. He wrote: “TV ratings are down, and I think we can point to the NFL legislating the emotion out of the game as a contributing factor. The NFL is enforcing a policy against celebration.

“Part of the problem is that players are being told to ‘act like they’ve been there’ by a group of people who have never been there themselves – Roger Goodell chief among them. I also think one of the things that needs to happen is for Roger Goodell to give up some of his power. He’s not an all-seeing, all-knowing, all-powerful being. He’s human, and I think he needs help dealing with the issues facing the league – from unsportsmanlike conduct to domestic violence.

“The real problem with the NFL is the lack of a system of checks and balances. The commissioner simply has too much power.”

Sherman also picked up an unlikely fan this week. In honor of Halloween, and his young son, the cornerback dressed up as Harry Potter for the Seahawks press conference earlier this week. It was enough for JK Rowling gave her approval. “Did I ever mention that I’m a #Seahawks fan?,” wrote the author in a tweet. “Well, I am, (Don’t ask me who plays for them apart from R Sherman.)” © Guardian News and Media Limited 2010