Tennessee's Week 5 game against the Buffalo Bills appears in further doubt following reports of another positive coronavirus case for a Titans player.

An outbreak within the Titans organisation last week led to their Week 4 game against the Pittsburgh Steelers being postponed until later this month.

Mike Vrabel's team are yet to return to their facility following the spate of positive tests and, on Thursday, NFL Network and ESPN both reported a fresh instance of a player contracting COVID-19.

In addition, an inconclusive positive test from Wednesday has now been confirmed as a definite positive, meaning that, since September 24, Tennessee have had 12 players and nine personnel staff contract the virus.

Whereas other teams have reported isolated or just a few cases, the Titans' large number has led to an NFL investigation into the possible cause of the outbreak.

Tennessee, who have started 3-0, are due to host the 4-0 Bills on Sunday in Nashville but, given they have been unable to practice at their facility, it seems likely that game will have to be postponed.

That will cause problems with the NFL's schedule given the Titans were given their one bye in Week 4 when their game against the Steelers could not take place.

Should the Bills be handed their bye this week, their next game will be a crucial Thursday Night Football showdown with a Kansas City Chiefs team who would be playing their third game in 11 days.

The defending Super Bowl champions played the New England Patriots on Monday - a day later than planned because of positive COVID-19 tests for both teams.

Stephon Gilmore became the second high-profile Pats player to return a positive test on Wednesday after quarterback Cam Newton did so last week, but there were reports every Patriots player tested negative when the latest results were returned on Thursday.