The Miami Dolphins hailed backup quarterback Ryan Fitzpatrick as their "relief pitcher" after Week 16's win over the Raiders, but if the team needs late-game heroics against the Buffalo Bills on Sunday, they'll have to count on someone else. As NFL Network reported Thursday, Fitzpatrick has tested positive for COVID-19 and will miss Week 17's crucial contest. The veteran was a surprise absence at practice earlier in the day, and now he won't be available for Miami until at least the postseason -- if the Dolphins make it. According to NFL Network's Tom Pelissero, the NFL's COVID-19 protocols require a 10-day isolation by players who've contracted the virus, meaning Fitzpatrick may also be sidelined for a potential AFC Wild Card game on Jan. 9 or 10. Coach Brian Flores had already named rookie Tua Tagovailoa the starter for Sunday's game, but Fitzpatrick has arguably been the Dolphins' better signal-caller, not to mention a repeat fill-in during Tagovailoa's lesser performances. In deeming him a "relief pitcher," after all, Flores left the door open for more Fitzpatrick playing time. There's been no word yet whether Tagovailoa himself could be considered a high-risk close contact to Fitzpatrick, which would also jeopardize his availability against Buffalo. In the meantime, the Dolphins will call upon veteran reserve Jake Rudock, who's only thrown five career passes, to serve as Tagovailoa's backup in Week 17. Rudock has been on and off Miami's practice squad this year but has been re-signed in the wake of Fitzpatrick's COVID test results, per Pelissero. SUBSCRIBE TO OUR CHANNEL: https://www.youtube.com/user/CBSSportsHQ FOLLOW US ON: Facebook - https://www.facebook.com/CBSSports/ Instagram - https://www.instagram.com/cbssports/ Twitter - https://twitter.com/CBSSports