SANTA CLARA – An extra bit of COVID-19 precaution has been found on the 49ers’ faces in practices this week. Their facemasks, specifically.

Because they played last Thursday night against a Green Bay Packers linebacker who later tested positive, the 49ers went into the NFL’s seven-day “intensive” protocol for COVID-19 prevention.

That ends Friday, so Thursday’s practice was their final one with mouth shields added onto facemasks. Oakley’s clear plastic swath has holes to aid in breathing while allegedly mitigating risk of coronavirus transmission from mouths.

That safety measure was not the result of the 49ers’ own COVID-19 case involving wide receiver Kendrick Bourne.

Bourne went back on the NFL’s COVID-19 reserve list Monday for a positive test. He has since tested negative, and if he continues to do so, he might be cleared in time to practice Friday and fly on the team charter to New Orleans for their game Sunday against the Saints.

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Last week, Bourne became the first 49ers player this season to go on the COVID-19 list, and, subsequently, three other players joined him on that list as high-risk contacts, those being Brandon Aiyuk, Deebo Samuel and Trent Williams.

Bourne and those three players all came off the COVID-19 list Friday after multiple tests with negative results. All, however, could not play nor attend Thursday’s 34-7 loss to the Packers.

The Packers and Pittsburgh Steelers also are practicing this week with mouth shields in the wake of positive tests among their players.

Those shields are not mandatory for games, and the 49ers (4-5) will not be wearing them Sunday when they visit the Saints (6-2).

Since the summer, the league has recommended face shields be worn as a protective measure. Only a couple 49ers experimented with them during training camp.

All players and coaches must wear masks (not neck gaiters) or the Oakley shield on the practice field. Players can remove their helmets and masks during breaks but must maintain a 6-foot distance from others, and coaches are responsible for monitoring this, according to league protocol.

Off the field, masks must be worn at all times, such as in meetings, in the weight room and in the locker room. An exception: the showers.

The league confirmed Wednesday that the 49ers do not face any discipline in the wake of Bourne’s potential mask violation last week following an investigation because of his initial positive test.