The NFL players union on Sunday criticised unofficial workouts conducted by star quarterbacks Tom Brady and Russell Wilson, saying the practices were risking player safety during the coronavirus crisis.

Tampa Bay Buccaneers star Brady and Seattle Seahawks signal-caller Wilson have both faced scrutiny recently after conducting throwing sessions with receivers in the build-up to official pre-season training camps.

However NFL Players Association executive director DeMaurice Smith told USA Today in an interview on Sunday that the sessions were potentially compromising players and the upcoming season.

“Those practices are not in the best interests of player safety,” Smith said. “They’re not in the best interests of protecting our players heading into training camp and I don’t think they’re in the best interests of us getting through an entire season.”

Smith said the practices could complicate the NFLPA’s negotiations with the league over how players who contract Covid-19 will be classified and compensated.

“I certainly understand how competitive our players are and I get that,” Smith said. “But at the same time we are in the process of trying to negotiate with the league about what happens to a player if they test positive during the season.

“Does that player go on injured reserve? Does that player go on short-term IR? If you test positive for the virus after training camp, is that a work-related injury? Are you covered under worker’s comp?

“What benefits are available to you if you have downstream injuries from contacting Covid-19?

“All of the things that players may want to do during the offseason have a direct impact on how well we can negotiate protections for them once the season starts.”

Brady meanwhile appeared to address the criticism with a post on Instagram last week which showed a picture of his latest workout accompanied by the quote from former President Franklin Delano Roosevelt: “The only thing we have to fear is fear itself.”