Bosa, who is unvaccinated, must quarantine for five days, per the NFL's COVID-19 protocols. As long as he continues to test negative and stays symptom-free, he would be eligible to return to the team Saturday at the earliest and play Sunday night against the Pittsburgh Steelers.
Bosa was determined to be in close contact with defensive lineman Jerry Tillery, who also was placed on the reserve/COVID-19 list Tuesday after testing positive, Staley said.
"They're both feeling well," Staley said, adding that defensive lineman Christian Covington also will be added to the reserve/COVID-19 list.
Staley said Covington had a positive test, followed by a negative test and then another positive test, putting his status in question.
The Chargers say Bosa has been diligent about wearing a mask when required and that anytime he didn't -- for a postgame news conference, for example -- was a simple mistake.
Staley said he is unaware of any talk of fines for the Chargers.
Bosa is tied for the league lead with three strip sacks and has 5.5 sacks this season. He has a sack in two straight games and three in the past four. Tillery has started eight games and is third on the team with eight quarterback hits. He also has 2.5 sacks.
The Associated Press contributed to this report.