The Vikings plan to be back at practice Thursday and play in Houston on Sunday, days after eight positive COVID-19 cases from their previous opponent forced them to close their team headquarters for two days.

General Manager Rick Spielman said Wednesday the Vikings are “optimistic we’ll be back in the building” Thursday for their first on-field practice of the week, after positive test results for three Tennessee Titans players and five staff members sent the Vikings scurrying to close their facility down Tuesday morning. Coaches worked from home Tuesday on a game plan for the Vikings’ next opponent, the Houston Texans, and conducted virtual meetings with players Wednesday.

Team infection control officer Eric Sugarman said the Vikings will have “enhanced protocols” in place Thursday, adding no one will be admitted inside the team headquarters without a negative PCR test in the last 24 hours and negative point-of-care test when they arrive.

Players, coaches and team personnel will continue to wear contact tracing devices that help NFL teams quickly determine who might have been exposed to a person who tests positive.

The Vikings had no positive COVID-19 cases through Tuesday’s tests, though it could be several days before the team can rule out the possibility anyone contracted coronavirus from the Titans game on Sunday.

The Titans added linebacker Kamalei Correa to their COVID-19 reserve list Wednesday, and the NFL announced it would move Tennessee’s home game against the Steelers from Sunday to Monday or Tuesday. It is the first COVID-19 postponement of the NFL season.

Virus outbreak delays Titans-Steelers to Monday or Tuesday

Because the virus can take several days to show up on a test after initial exposure, the Vikings can’t be sure yet they won’t have any positive cases as a result of Sunday’s game.

“The CDC website will tell you that symptoms appear anywhere from day two to day 14 as well [through] a positive test,” Sugarman said. “It seems like the sweet spot for a positive is between days three and five. So Thursday, Friday, Saturday, Sunday are critical days for us. And we’ll see what happens, and we’ll also have an eye on the Titans as well.”

Sugarman said sports are considered a low-risk activity because of their lack of sustained proximity to opponents, though football, which puts players in close contact for a few seconds at a time throughout a game, carries more risk than other sports.

Three of the players on the Titans’ COVID-19 reserve list — Correa, defensive tackle DaQuan Jones and long snapper Beau Brinkley — played Sunday. Jones was on the field for 69% of the Titans’ defensive snaps, Correa played 19 snaps on defense and special teams, and Brinkley played 10 special-teams snaps.

Tennessee learned Saturday morning that a coach had tested positive, and he did not travel with the team to the Twin Cities. The NFL tests players and staff Monday through Saturday, with results available within 24 hours, but does not test on game days.

Sugarman said the Vikings had several “moderate-risk contacts,” but those were primarily among coaches and team personnel talking with their counterparts from Tennessee before or after the game.

He called Vikings’ situation “a case study.”

“We have a known positive case that played in the game, and I think everyone is interested to see what’s going to happen, if anything,” Sugarman added.

If the Vikings have one or two positive tests this week, the team likely would proceed as normal by isolating those individuals with a care package, Sugarman said, adding there is no set number of positive tests to determine whether the team headquarters would need to remain closed.

Nor is there a threshold for moving the Vikings’ game against the Texans to a later date, Spielman said. As of now, he said, the Vikings are planning to practice this week and head to Houston on Saturday as they normally would. The team could practice Thursday and Friday and stage a shortened version of its normal Friday practice on Saturday before departing, he added.

Coach Mike Zimmer said Wednesday afternoon: “We had basically all day to meet with the players today and had quite a bit of meeting time. What we’ll do is have a little less meeting time, and a little more walk through and practice time in the next couple days.”

Spielman said he spoke to NFL executive vice president of football operations Troy Vincent about the fact the Vikings would have less time to prepare than the Texans. The league’s position, Zimmer said, is that teams have faced practice week disruptions because of natural disasters such as hurricanes or wildfires and still gone on to play as scheduled.

“The precedent has been set that those other teams went about their business and the [affected] team had to figure out a way to survive and move forward,” Zimmer said. “That’s kind of the precedent that they set, so that’s what it is.

“This happened, unfortunately to us, but not because of us. But it is what it is and we have to deal with it. I think moving forward, they told us all along there was going to be positive tests and so on and so forth as we go throughout the season. But for us to be able to get through — hopefully we get through this week — but get through this week and play the game, I think it kind of shows we can get through it.”