NASHVILLE -- The NFL's investigation into how Tennessee turned into the league's first COVID-19 outbreak found 鈥渟everal specific incidents鈥� of the Titans possibly breaking protocols dealing with the coronavirus pandemic, according to a person with knowledge of the probe.

Also, the headmaster of a private school in Nashville confirmed to The Associated Press on Wednesday that several Titans, including quarterback Ryan Tannehill, practiced on its field Sept. 30. That was a day before the NFL first postponed Tennessee's game with Pittsburgh before rescheduling to Oct. 25.

NFL Commissioner Roger Goodell warned all 32 teams Monday that following league protocols is mandatory and that violations forcing changes in the schedule could lead to forfeiting games.

Tennessee had two more players test positive Wednesday, a person familiar with the the situation said. The Titans placed starting wide receiver Corey Davis on the reserve/COVID-19 list hours later, bringing their total to 22 cases with 20 returned since Sept. 29.

The Titans cannot return to their facility before Saturday at the earliest, needing back-to-back days without a positive test result. They haven't been on a field since beating the Vikings 31-30 on Sept. 27. The NFL has to decide if they play Buffalo (4-0) as scheduled Sunday, postpone and reschedule or forfeit.

Titans coach Mike Vrabel said Tuesday any discipline would be something for the NFL to discuss.

鈥淚 don't expect anything either way,鈥� Vrabel said.

The Titans were featured with 鈥渟everal specific incidents鈥� during a call Monday with the league's general managers and coaches, a person with knowledge of the NFL's investigation said. Another person familiar with the call said photos from the Titans' cafeteria were shown.

Both spoke to The Associated Press on condition of anonymity because the investigation is ongoing.

The league is attempting to play a full schedule amid the pandemic without teams isolated in a bubble as other sports have done to protect players and staff from the virus. No games were affected through the first three weeks of the season.

Dr. Allen Sills, the NFL's chief medical officer, told Judy Battista of the NFL Network the league has looked into everything from video inside the Titans' facility, interviewing everyone involved and even studied seating charts on buses and planes.

Sills also made clear the league expected positive cases all along.

鈥淭he exercises are not just about did someone follow the protocols or not but, are there vulnerabilities we can tighten up, what can we learn and where can we get better and how can we improve going forward,鈥� Sills said. 鈥淎nd we've already made a number of those changes.鈥�

Minnesota coach Mike Zimmer said his Vikings went over the new protocols Wednesday for clubs having been been exposed to a team dealing with a COVID-19 outbreak. Having played Tennessee helps his Vikings understand the significance of following the league's guidelines to stay safe.

鈥淵ou look at the Pentagon, they've got it. The White House has got it. The NFL has got it,鈥� Zimmer said. 鈥淚t's a crazy time.鈥�

The Patriots are dealing with their own COVID-19 cases. Cornerback Stephon Gilmore, the 2019 Defensive Player of the Year, announced on social media he had tested positive and is asymptomatic. Quarterback Cam Newton was placed on the reserve/COVID-19 list Oct. 3, with a defensive tackle from the practice squad added Tuesday.

New England cancelled practices Wednesday and Thursday. They are scheduled to host Denver on Sunday.

The NFL already postponed the Patriots' last game a day before New England lost in Kansas City 26-10 on Monday night. The Chiefs host the Raiders on Sunday; Las Vegas placed defensive tackle Maurice Hurst on the reserve/COVID-19 list Tuesday.

Newton and the Titans make up the 11 confirmed positive tests among players from testing last week. The NFL also said there were 15 new confirmed positives among personnel in results announced Wednesday out of 37,002 tests given to 7,981 players and team personnel last week.

Both Sills and Dr. Thom Mayer, the NFL Players Association's medical director, said the key is everyone following the protocols.

鈥淭he virus is still very much a threat not only to our season, but to the safety of everyone in our community,鈥� Mayer said in a statement.

Buffalo coach Sean McDermott is busy preparing his Bills until told differently. He said no one's perfect and they're all fighting an uphill battle with how easily COVID-19 spreads. His Bills have had no positives after beating the Raiders 30-23 in Las Vegas last week.

鈥淲e have a lot of trust and faith in the league,鈥� McDermott said of playing a game in Tennessee.

Pushing Bills-Titans to Monday night is challenging because Buffalo is scheduled to host Kansas City on Thursday, Oct. 15. That would force the NFL into further rearranging of the schedule.

The Bills aren't thinking of a forfeit right now.

鈥淲e'll handle that when the time comes,鈥� Bills safety Jordan Poyer said. 鈥淩ight now, we're acting like we're playing. And when that moment comes, where they tell us this, that or the other, I think that's when we'll worry about it.鈥�

Bills quarterback Josh Allen said this virus can be as simple as one person going to a grocery store, and Baltimore wide receiver Marquise Brown said the test results show how cautious players must be away from the team facility.

鈥淚t's not just about you,鈥� Brown said. 鈥淚t's about the whole NFL.鈥�

Asked about the chances of the , Miami quarterback Ryan Fitzpatrick said he thinks everyone is very interested in what happens the next few days.

鈥淓verybody's confidence level is probably a little less than a few weeks ago,鈥� Fitzpatrick said. 鈥淭wo weeks ago everybody was riding high. It's amazing to see what happened in Tennessee so quickly.鈥�

Cleveland quarterback Baker Mayfield had a simple suggestion to keep all of the NFL playing.

鈥淛ust wear your masks,鈥� Mayfield said. 鈥淲e all want to play football. Everybody has to do it. Just do it.鈥�

------

AP Pro Football Writers Barry Wilner and Dave Campbell and Sports Writers Dave Ginsburg, Kyle Hightower, Will Graves, John Wawrow, Steve Wine and Tom Withers contributed to this report.