OWINGS MILLS, Md. -- The Baltimore Ravens are headed to Pittsburgh after no players tested positive for COVID-19 on Tuesday, a source confirmed.

This ends a stretch in which the Ravens had at least one player test positive for nine straight days.

The Ravens are now set to play the undefeated Steelers in a game that has been postponed three times because of the outbreak in Baltimore. At least one dozen Ravens have tested positive, including reigning NFL MVP Lamar Jackson.

Baltimore practiced early Tuesday and then awaited the latest test results. Once cleared, the Ravens headed to the airport around 5 p.m. Tuesday, a source told ESPN's Dianna Russini.

The Washington Post was the first to report no new positive tests for Ravens players.

The news came hours after Baltimore activated nose tackle Brandon Williams, quarterback Trace McSorley and injured cornerbacks Tavon Young and Khalil Dorsey from the reserve/COVID-19 list.

The Ravens trimmed the number of players on the reserve/COVID-19 list to 16 players, which marks the first time they have reduced the number of players on this list since the outbreak in Baltimore began Nov. 22.

The Ravens announced later Tuesday that Williams will not play against Pittsburgh. The Ravens' starting nose tackle hasn't practiced since injuring his ankle in a 23-17 loss in New England on Nov. 15.

McSorley, who was on the reserve/COVID-19 list for 10 days, gives Baltimore two quarterbacks on the active roster. Robert Griffin III is expected to start in place of Jackson, who tested positive for COVID-19 on Thanksgiving. If McSorley is unable to back up Griffin, Baltimore would promote undrafted rookie Tyler Huntley from the practice squad.

Young and Dorsey revert to injured reserve after coming off the reserve/COVID-19 list.

Baltimore is in the midst of one of the biggest outbreaks in professional sports. At least a dozen Ravens players have tested positive over the past 10 days.

The Ravens also announced that two assistant coaches -- Joe D'Alessandris (offensive line) and Matt Weiss (running backs) -- did not travel to Pittsburgh due to illness.