The NFL's COVID-19 outbreak hit an all-time high on Monday.

There were 36 players and one staff member across the league that tested positive for the coronavirus on Monday, the most ever in a single day since the pandemic began in 2020, according to the NFL Network's Tom Pelissero.

The staff member reportedly tested positive for the Omicron variant, which marks the first known case of that variant in the league.

The NFL also officially announced Monday that all Tier 1 and 2 staff members must receive a booster shot by December 27.

The NFL isn’t alone in dealing with new coronavirus outbreaks. The NBA on Monday postponed two games for the Chicago Bulls after 10 players entered the league’s health and safety protocols. The Charlotte Hornets have also been dealing with a similar outbreak in recent weeks.

Coronavirus cases are surging back up across the United States in general. As of Monday afternoon, the country is averaging nearly 120,000 new cases each day, according to The New York Times, which marks a 43% increase over the past two weeks. About 70% of Americans aged 12 and up are fully vaccinated.

Chargers tackle Rashawn Slater tests positive

The Los Angeles Chargers placed left tackle Rashawn Slater on the reserve/COVID-19 list on Monday, according to the NFL Network’s Taylor Bisciotti.

Chargers coach Brandon Staley confirmed that Slater was one of the 36 players who tested positive for the coronavirus, just one day after their 37-21 win over the New York Giants.

It’s unclear how long Slater will be sidelined, but it’s likely a stretch that he’ll be able to return in time for the Chargers’ Thursday night matchup with the Kansas City Chiefs. Staley, however, did not rule that out. If he is vaccinated, Slater will need to test negative two times at least 24 hours apart and be asymptomatic for 48 hours before he can return.

Slater, who the Chargers took with the No. 13 overall pick in the draft earlier this year, has played in every single snap for the team so far this season. The former Northwestern standout has been a big part of protecting quarterback Justin Herbert, who is third in the league in yards thrown and tied for second in touchdowns so far this season. Herbert threw for 275 yards and three touchdowns in their win over the Giants on Sunday.

With Slater likely out, the Chargers will turn to Trey Pipkins against the Chiefs — where they’re listed as a +4 underdog on BetMGM. Pipkins, who is in his third year with the team, has played just 27 snaps this season.

Chargers wide receiver Keenan Allen is still on their reserve/COVID-19 list. He did not play against the Giants. Receiver Mike Williams and cornerback Chris Harris were deemed close contacts of Allen’s last week and also landed on the list, though both were cleared in time and played on Sunday.