Contract tracing reportedly is ongoing for both teams.
On the same day that the Patriots and Titans returned to their facilities, two other NFL teams have registered positive COVID-19 tests.
According to ESPN's Adam Schefter, a member of the Bears' practice squad and a Chiefs strength and conditioning coach have tested positive. Contract tracing is ongoing for both teams.
The Chiefs are set to host the Raiders on Sunday afternoon, while the Bears last played on Thursday night in a 20–19 win over the Buccaneers.
The news comes as the league appeared to bounce back from outbreaks in Tennessee and New England. Neither team reportedly registered positive results from Friday's COVID-19 testing.
Since late September, the Titans have had 23 cases of positive tests, including 13 from players. The outbreak prompted an investigation from the NFL and resulted in two of their games being rescheduled.
Coach Mike Vrabel announced the team's enhanced safety protocols on Saturday, including moving 30 lockers to their indoor practice bubble to create more space in the locker room. Players must have a POC rapid test to enter the building and everyone must wear face masks during in-person meetings.
New England practiced in person on Saturday after closing the facility for three days and working out virtually. Coach Bill Belichick said quarterback Cam Newton and cornerback Stephon Gilmore wouldn't practice on Saturday, but he dodged questions about who will start against the Broncos on Monday if Newton is still out.
Newton, Gilmore and practice squad defensive tackle Bill Murray remain on New England's reserve/COVID-19 list. After Gilmore tested positive on Wednesday, the Patriots' Week 5 game against the Broncos was moved to Monday night.