GREEN BAY, Wis. -- The Green Bay Packers could potentially be without Aaron Rodgers' most important target for their biggest game of the season Thursday at Arizona after receiver Davante Adams was placed on the reserve/COVID-19 list Monday.

Adams tested positive for COVID-19, a source told ESPN's Adam Schefter. Adams hasn't been forced to follow protocols for unvaccinated players, an indication that he is vaccinated.

If Adams is indeed vaccinated and is asymptomatic, he would need two negative PCR tests 24 hours apart to play Thursday against the unbeaten Cardinals. Arizona activated pass-rusher Chandler Jones, who is second on the team with five sacks, and defensive lineman Zach Allen from the reserve/COVID-19 list Monday.

This news on Adams came shortly after Packers coach Matt LaFleur said the team is expected to be without defensive coordinator Joe Barry for Thursday's game at Arizona because of COVID-19 rules.

LaFleur also said the team has entered enhanced mitigation protocols that call for daily testing of all personnel and for masks to be worn at the facility. The Packers held all meetings virtually the day after their 24-10 win over the Washington Football Team, and LaFleur said there are "potentially some other issues with the [coaching staff]."

At that time, he said there was not a significant concern that it would impact players. Less than two hours later, Adams was placed on the list.

"Any time that you have any cases, you're always a little bit concerned about that," LaFleur said. "But the majority of our guys are vaccinated, so there's a little bit different protocol with that. I don't think in terms of being at close contact with any of our players, I don't think that's a real concern of ours right now. But we're still waiting to hear back from the league before we get clearance on anything."

Adams leads the Packers in catches (52) and receiving yards (744). He is tied for second in the NFL in catches and alone in third in yards among all receivers.

The Cardinals move from a 4.5- to a 6-point favorite vs. the Packers at Caesars Sportsbook with the Adams news.

The Packers are hopeful that receiver Marquez Valdes-Scantling could return this week from a hamstring that has kept him out the past four weeks.

LaFleur said the defensive playcalling will be a "collective effort with everybody involved and having an input." Defensive backs coach Jerry Gray, who was promoted to passing game coordinator this season, likely will take the lead, assuming he is available to coach. He was a defensive coordinator with the Buffalo Bills (2001-05) and Tennessee Titans (2011-13) whom LaFleur considered for that job in Green Bay before he hired Barry.

All NFL coaches must be vaccinated, and Barry, like Adams, will require two negative tests 24 hours apart before he could return. The Packers are scheduled to depart for Phoenix on Wednesday.

The Packers (6-1) are facing their toughest test of the season in the Cardinals (7-0) and their dynamic quarterback, Kyler Murray. Green Bay ranks seventh in total defense and in fewest points allowed after its win over Washington.

Barry's defense finally fixed some of its red zone issues on Sunday, as well. The Packers had allowed touchdowns on 15 straight red zone drives entering Sunday -- the first team in at least 40 years that didn't get a single red zone stop in its first six games of a season -- but came up with four straight red zone stops against Washington, including a stuff on fourth-and-goal from the 1.

Barry is the second member of the Packers' defensive coaching staff to test positive for COVID-19 this season. Defensive line coach Jerry Montgomery missed the Week 2 game against the Detroit Lions because of a positive test.