The Browns (6-6) also could be without tight end Harrison Bryant, who suffered a high ankle sprain in Week 12 against the Ravens in a 16-10 loss, the Browns' most recent game before their bye last week. Njoku had a touchdown reception in that game.
It wasn't announced if Njoku tested positive for COVID-19 or if he is being placed on the list as an unvaccinated close contact.
If he is vaccinated and tested positive, he can return once he is able to produce two negative tests 24 hours apart. If he's unvaccinated and tested positive, he would be sidelined for a minimum of 10 days. If he is a close contact, he must quarantine for five days and can return after that time period if he produces a negative test.
Njoku leads the Browns with 407 receiving yards this season and is third on the team with 27 receptions. He also is tied for the team lead with three touchdown receptions.
The Browns signed Miller Forristall to the active roster in a corresponding move. The Browns also have starting tight end Austin Hooper, who is second on the team with 28 receptions and has 261 yards and two touchdowns, on the active roster.