Quarterback Patrick Mahomes of the Kansas City Chiefs wears a mask on the sidelins of a game on September 10, 2020, in Kansas City, Missouri.
CNN  — 

The NFL is recommending that players not in a game or about to enter a game wear face coverings while on the sideline, as players across the league continue to test positive for Covid-19.

In a memo obtained by CNN on Friday, the league’s management council told teams, “A player wearing a mask during a close contact has a significantly reduced probability of being designated a “High Risk Close Contact” after an exposures to a COVID-positive individual.”

In a recent case of a player who tested positive two days after a game, contact tracing revealed that the player had close contacts with 17 teammates and 2 members of the team’s staff, none of who were wearing masks.

“Although the experts have determined that the positive player’s testing history established that he was likely not contagious on game day (he had a negative test on game day as well as the days before and after), the number of potential “High Risk Close Contacts” identified by this exercise is concerning as it relates to potential exposure and transmission,” according to the memo.

The league is looking to work with teams to expand the bench areas in an effort to encourage physical distancing among players and staff.

The NFL’s main goal is to “work collectively to identify areas of vulnerability for transmit,” said Chief Football Administrative Officer Dawn Aponte Friday on a conference call. Mask wearing and distancing would be critical to the success of the rest of the NFL season, she said.

The recommendation comes as almost 50 players and more than 70 personnel members have tested positive for the virus since monitoring testing began on August 1.

Games have had to be rescheduled, and some teams have had to temporarily suspend in-person activities due to outbreaks.

On Friday, the Denver Broncos canceled practice after a player tested positive for Covid-19. In a statement, the team says the player in question is at home self-isolating as are two other teammates who have been in close contact with the unnamed player.

The Broncos are set to host the Los Angeles Chargers on Sunday.

CNN’s David Close contributed to the report.