The Cardinals placed receiver KeeSean Johnson on the reserve/COVID-19 list on Sept. 11. They activated him from the list Monday, the team announced.
The 2019 sixth-rounder caught 21 passes for 187 yards and a touchdown as a rookie.
The Cardinals placed tight end Maxx Williams (ankle) on injured reserve in a corresponding move. Williams will have to miss three games before becoming eligible to return.
He played 43 snaps in the season opener before being inactive for the Week Two game Sunday.
In addition, the Cardinals signed tight end Justin Johnson to the practice squad and placed running back D.J. Foster (quadricep) on the practice squad injured reserve list.