League sources told ESPN and NFL Media that Tomlin was diagnosed last week. The Steelers didn't immediately confirm the diagnosis but said members of the coaching staff and other personnel were sent home from the facility last week after several positives came up in routine testing.
Tomlin later confirmed his diagnosis with a statement on social media. The 48-year-old coach said he is dealing with "minimal" symptoms.
"I want to thank everyone who reached out to express their concern for my health," Tomlin said Monday night. "Luckily I have had minimal symptoms and I'm thankful to be in good health. I want to thank those media professionals who knew about my situation and respected my privacy. It is very much appreciated.
"I'll be back in the office soon while I continue to work virtually from my home. Thanks for your support and well wishes!"
Tomlin, who is set to enter his 15th season as head coach of the Steelers, guided the franchise to a 12-4 record this past season. Pittsburgh fell to the division rival Cleveland Browns in the AFC wild-card round.
The coronavirus previously impacted the Steelers' coaching staff during the 2020 season, with then-quarterbacks coach Matt Canada and special teams coordinator Danny Smith missing time because of the league's COVID-19 protocols.