The NFL Players Association has fired back at the league after the NFL issued a memo regarding the season-ending injury suffered by Denver Broncos offensive tackle Ja'Wuan James.

In a memo Wednesday, the league said that James, who reportedly tore his Achilles while working out away from team facilities, lost his guaranteed salary because he was injured while working out away from the team. 

The NFLPA sent an email to players Thursday calling the response "gutless," deeming it "a scare tactic to get you to come running back to these workouts": 

The union has been urging teams to boycott in-person workouts in favor of a virtual offseason program similar to the one implemented in 2020 amid the COVID-19 pandemic.

James, who opted out of the 2020 season due to the pandemic, stands to lose up to $20 million, according to ESPN's Adam Schefter. The league's response drew the ire of players, including Kansas City Chiefs quarterback Patrick Mahomes: 

Yet the rule the league reminded players of in the memo has been in place since 1977, according to Mike Florio of Pro Football Talk. 

Still, the NFLPA's response said James was "working out to stay in shape under a program recommended to him by his coach," and said "clubs who care about their players" have ignored the rule in similar circumstances. 

Most teams have issued statements through the NFLPA that they will not participate in in-person workouts.

The union said there was a 23 percent decrease in missed-time injuries and 30 percent decrease in concussions without an in-person preseason (h/t Mary Kay Cabot of Cleveland.com).