The Vikings got good news Saturday morning, when another two rounds of COVID-19 testing turned up no positive cases before players took part in an extended walk-through and boarded the flight to Houston for Sunday's game against the Texans.

Friday's PCR tests and Saturday morning's point-of-care tests turned up negative results for all the Vikings nearly a week after they played the Tennessee Titans, whose outbreak has grown to 18 players, coaches or team personnel since Sept. 24 after another three people tested positive Saturday.

While some Vikings coaches and staffers had "moderate-risk contacts" with the Titans before and after last weekend's game, athletic trainer and infection control officer Eric Sugarman said last week that in-game contact between players is often brief and that the team viewed pregame and postgame conversations as longer, higher-risk contacts.

The Titans are up to nine positive cases among players, including at least six who played against the Vikings.

An additional eight Titans personnel have tested positive since outside linebackers coach Shane Bowen did — a day before the Vikings game.

Sugarman pinpointed Thursday, Friday, Saturday and through Sunday as critical days for the Vikings based on how long COVID-19 can take to show up on a test. The Vikings will be the first NFL team to be tested on game day, according to updated NFL guidelines for teams affected by or in close contact with the virus.

Boyd to miss game

The Vikings downgraded cornerback Kris Boyd to out on Saturday because of the hamstring injury he played through last week against the Titans, and they added receiver Tajae Sharpe as a late scratch because of an illness.

Boyd was already listed as doubtful after getting his first NFL start against Tennessee. Sharpe practiced and wasn't listed on the injury report until he turned up ill Saturday.

The Vikings already had ruled out cornerback Mike Hughes for a second straight game because of a neck injury. Hughes' 2019 season ended because of a fractured vertebra in his neck.

Safety George Iloka has been elevated from the practice squad and will be available for Sunday's game.