Barnes played on Thursday night against the 49ers but exited in the second quarter with a calf injury.
Packers rookie linebacker Krys Barnes has tested positive for COVID-19, according to NFL Network's Ian Rapoport.
ESPN Adam Schefter was first to report an unnamed Packers player returned a positive test on Friday, one day after Green Bay's 34–17 win over the COVID and injury-plagued 49ers.
Barnes, who dealt with shoulder and biceps injuries this week, exited in the second quarter with a calf strain. He had three tackles before he was forced to leave the game and was later ruled out to return against San Francisco.
According to Rapoport, Barnes was unable to undergo an MRI for his calf strain on Friday because of his positive COVID-19 test. He will have to wait to learn more about his injury.
On Monday, Packers running back AJ Dillon tested positive for COVID-19 following their loss to the Vikings the day before. Dillon's positive result reportedly came from Sunday's pregame COVID-19 testing ahead of the game, however, the results of game-day tests don't return until Sunday evening or early Monday.
The Packers later added running back Jamaal Williams and linebacker Kamal Martin to the COVID-19/reserve list as high-risk contacts.
Dillon wasn't the only player in the league to return a positive test following Sunday's games. Ravens cornerback Marlon Humphrey also announced on Monday that he tested positive for COVID-19 after playing against the Steelers.
The NFL continues to battle COVID-19 cases around the league as the Dolphins, Falcons and Bengals announced on Friday that members of their organizations have tested positive for COVID-19. Miami and Atlanta have entered intensive COVID-19 protocol following the tests, and Cincinnati is on a bye week.