OWINGS MILLS, Md. -- The Baltimore Ravens announced they closed their facility Monday after learning that multiple members of the organization have tested positive for COVID-19.

There have been at least four positive tests including players and staff members, a source said. The team was notified of the tests Sunday night, just hours after Baltimore's 30-24 overtime loss to the Tennessee Titans.

Those individuals have begun to self-quarantine, according to the team.

It is unknown how this will affect Thursday night's game against the undefeated Pittsburgh Steelers. Those who tested positive would not play Thanksgiving night, nor would those identified as high-risk close contacts, who require five days of isolation.

The Ravens have begun the process of contact tracing. All activities are being handled virtually.

Baltimore canceled a scheduled 4:30 p.m. practice Monday. If the schedule remains unchanged, the Ravens would have one practice Tuesday before traveling to Pittsburgh on Wednesday.

Third-string quarterback Trace McSorley was the last player placed on the reserve/COVID-19 list. He didn't practice Thursday or Friday last week because he was close to someone who had tested positive.

Before this week, the Ravens had only two players test positive during the regular season: All-Pro cornerback Marlon Humphrey (Nov. 2) and cornerback Iman Marshall (Nov. 12). Marshall has been on injured reserve all season.

This has already been a trying season for the Ravens (6-4), a team that was among the preseason Super Bowl favorites but that has lost three of its last four games. If the two-time defending AFC North champions lose in Pittsburgh, they would be eliminated from the division race.