The Titans previously announced that seven players, including Tannehill, had been placed on the reserve/COVID-19 list this week and that coach Mike Vrabel tested positive for the coronavirus Sunday.
Tannehill, who is vaccinated, will miss five to 10 days depending on how quickly he can produce two negative tests over a 48-hour period. The Titans host the Arizona Cardinals in Week 1 on Sept. 12.
Tight end Geoff Swaim and linebacker Justin March-Lillard were placed on the reserve list Thursday along with Tannehill. The other Titans players on the reserve list are defensive tackle Anthony Rush, running back Jeremy McNichols and linebackers Nick Dzubnar and Harold Landry.
Vrabel, who said Thursday that he is feeling well but has not had a negative COVID-19 test, told reporters that special teams coach Craig Aukerman is in the COVID-19 protocol. Aukerman missed practice Wednesday and Thursday and won't be available for Saturday's preseason game against the Chicago Bears.
Earlier Thursday, general manager Jon Robinson said Tannehill was "feeling fine."
"He'll be engaged in the meetings. He'll ready to go," Robinson said. "He's a pro and has played in the league for a long time. We have the utmost confidence in him and his ability to prepare."
Tannehill said he was "in the process of getting vaccinated" when training camp started. He said at the time that he wouldn't have gotten the vaccine but that the NFL is "forcing players' hands" by instituting protocols.
The Titans were in Tampa, Florida, last week for joint practices with the Buccaneers. Former Titans kicker Ryan Succop, who is now a member of the Buccaneers, tested positive for COVID-19 and was added to the reserve list Monday. Succop went to dinner with three Titans players when they were in Tampa. None of the Titans players at the dinner have tested positive.
"We've followed the protocols," said Robinson, who noted that the Titans are approximately at 97% or 98% vaccinated. "Our medical team has done an outstanding job with talking to the league and the players, coaches."