Miami Dolphins QB Ryan Fitzpatrick tests positive for COVID-19, out vs. Buffalo Bills, per reports

DAVIE, Fla. -- Miami Dolphins veteran quarterback Ryan Fitzpatrick has tested positive for COVID-19 and will miss Sunday's game against the  Buffalo Bills, a source confirmed to ESPN.

The Dolphins and NFL have conducted initial contact tracing with no high-risk close contacts determined as of Thursday afternoon, a source told ESPN, but that process will continue. Fitzpatrick practiced fully Wednesday and wasn't listed on the injury report, but he didn't practice Thursday afternoon, indicating that the positive COVID-19 test was a recent surprise.

Rookie  Tua Tagovailoa is the Dolphins' starting quarterback, but Fitzpatrick has been called on twice in the fourth quarter to play what coach Brian Flores compared to a "ninth-inning reliever" role. Fitzpatrick led the Dolphins to a 26-25 comeback win over the Las Vegas Raiders on Saturday after a 34-yard heave coupled with a 15-yard face mask penalty set up the game-winning field goal.

The Dolphins signed Jake Rudock to the 53-man roster Thursday, and he is expected to be Tagovailoa's backup Sunday. Tagovailoa, Rudock and practice squad quarterback Reid Sinnett practiced fully Thursday.

NFL Network first reported Fitzpatrick's positive test.

The Dolphins would clinch a playoff berth with a win over the Bills. They could still make the playoffs with a loss but would need a loss from either the Cleveland Browns (vs. a  Steelers team resting key starters), Indianapolis Colts (vs. Jaguars) or Baltimore Ravens (vs. Bengals). The Bills, who have clinched the AFC East but can earn the No. 2 (vs. No. 3) seed based on Week 17 results, have been coy on whether they will play their starters.

Fitzpatrick, 38, is 4-3 as a starter this season, throwing for 2,091 yards with 13 touchdowns and eight interceptions.