The NFL office sent a memo to teams on Thursday, informing them that discipline could result if players fake injuries in an attempt to slow down opposing offenses.
NFL Vice President of Officiating Dean Blandino sent the memo in response to an admission by former Chicago Bears linebacker Brian Urlacher than his team faked injuries when he played.
The memo reminded clubs of Supplemental Note to Rule 4, Section 5, Article 4, which states that the NFL "deprecates" feigning injuries in an attempt to obtain a timeout without penalty.
"We have instructed all officials to be on the alert for violations of this rule," Blandino wrote in the memo, according to ESPN.com. "Further, if it is determined by video review or other means available to the League office that defensive players are engaging in such practices, such players and their coaches may be subject to disciplinary action."
Earlier this week, Urlacher has said his team faked injuries.
"We had a guy who was the designated dive guy," he said, according to the Chicago Sun-Times. "It wasn't coached, but it was part of our game plan."
Former Bears tight end Martellus Bennett told the Sun-Times, "Every team does that. Sometimes, it's just like when you're boxing. You get hit too many times, and you want to hold him up against the ropes. I think a lot of teams do that. You've got to do whatever it takes to win the game."