5:36 PM ET
The Steelers were informed of the positive test Monday morning, Steelers spokesperson Burt Lauten said in a statement.
McDonald immediately self-quarantined, Lauten said, and the team remains in the intensive COVID-19 protocol.
McDonald was placed on the reserve/COVID-19 list Monday, per the NFL transactions wire. He was first added to the injury report with an ‘illness’ on Friday. He still traveled and played 24 snaps Sunday against the Dallas Cowboys.
The Steelers first entered the intensive protocol — which requires players to wear face coverings during practice, among other heightened measures to stop the spread of the virus — last week after Ravens defensive back Marlon Humphrey returned a positive test shortly after playing the Steelers.
In that situation, Humphrey was sent home from the Ravens’ team facility on the Wednesday before the Steelers’ game after he reported “cold symptoms.” He then returned to practice Thursday and Friday before playing in 100% of defensive snaps against the Steelers. The NFL has maintained there is no evidence of on-field transmission,