The Vikings' desperate push for a playoff spot will continue Sunday without quarterback Kirk Cousins.

Cousins went on the COVID-19 reserve list Friday after testing positive for the virus and will miss Sunday night's game against the Green Bay Packers.

Backup quarterback Sean Mannion will start Sunday, coach Mike Zimmer said at a news conference Friday. Mannion was activated from the COVID-19 list Friday, in line with the league's new protocols that allow players to return in five days if their symptoms are resolving. Mannion, who is vaccinated, tested positive for COVID-19 on Sunday morning.

"We hate to see that happen to Kirk, but he's done a lot of great things for us," Zimmer said. "Sean is a really good football player, and we're expecting him to go out and play very well.''

Zimmer said he had not been told whether Cousins, who had been getting tested daily, is symptomatic.

Cousins, who is unvaccinated, had a previous brush with the COVID-19 protocols. He was placed on the list as a close contact early in training camp after Kellen Mond tested positive for the virus. After returning from a five-day quarantine, Cousins declined to discuss his decision on whether to be vaccinated, calling it a personal choice and saying his focus was on avoiding being a close contact.

After Mannion tested positive, Cousins admitted that staying clear of the virus before the Vikings' most important game of the season would be tough.

"It just is what it is," Cousins said on Sunday. "At this point, you just have to follow the protocols, be disciplined and there's a lot of people not testing. So, it's in our building. It's going to be in our building. It's going to spread. We've just got to be disciplined to keep our distance and make sure that to the best of our ability we don't get it, but it is going to be difficult."

Mannion, a third-round draft pick by St. Louis in 2015, has thrown passes in five NFL games in his five-year career, going 45-for-74 (60.8%) and accumulating 384 yards, three interceptions and no touchdown. He has appeared in 13 games and started two, both times the final game of a regular season. One went far better than the other.

In 2017 with the Rams, in a 34-13 loss to the 49ers, Mannion completed 22 of 37 passes with no interceptions for a 72.5 rating.

In 2019, the Vikings were locked into their playoff seed in the final week. They rested Cousins and a lot of starters in a 21-19 loss to the Bears. Mannion completed 12 of 21 passes for 126 yards, threw two interceptions and had a 35.1 rating. That was the last time Mannion appeared in an NFL game.

Zimmer indicated any changes would not be dramatic with Mannion stepping in for Cousins.

"Obviously, their game plan will change," he said. "We'll have to make some adjustments. Sean knows the game plan cold. Like I said, he's an extremely brilliant person. He puts in the work every single week like he's the starter, and he is this week."

Third-round pick Kellen Mond will be active for the second time this season as Mannion's backup, a week after he was Cousins' backup with Mannion out.

Zimmer said he's already working on keeping spirits up as an important game nears and an important player becomes unavailable.

"I talk to the team all the time," he said. "I talked to them a couple of times this morning. I'll talk to them tomorrow. I think they're going to rally behind Sean. They know how important this game is. They believe in Sean."

Zimmer said the more contagious omicron variant of COVID changed the late-season scenario for the team.

"It's way different than it was at the start of the season," he said. "I was more concerned about the players' health more so than losing football games or not having a player for that. I didn't want their families or them getting sick and really sick. It's changed. There are so many people getting it now. It's just part of life."

Cousins' placement on the COVID-19 list comes a week after running back Dalvin Cook, who is also unvaccinated, missed the team's loss against the Rams. Cook returned from the COVID-19 list in just six days, thanks to the league's relaxed protocols for unvaccinated players, and is scheduled to play on Sunday night against the Packers.