The NFL postponed the Baltimore Ravens’ game at the Pittsburgh Steelers for a second time because of a coronavirus outbreak on the Ravens.

The game now is scheduled to be played Tuesday at 8 p.m. Eastern time on NBC. The league announced the rescheduling Friday, although several people familiar with the situation cautioned that Baltimore’s outbreak must be contained for the game to be played Tuesday.

If the game is played Tuesday, the NFL announced, the Ravens’ following game against the Dallas Cowboys in Baltimore would be pushed from Thursday until the following Monday, Dec. 7, at 5 p.m. on Fox, NFL Network and Amazon.

“These decisions were made out of an abundance of caution to ensure the health and safety of players, coaches and game day personnel and in consultation with medical experts,” the NFL said in a statement.

The NFL also told teams in a memo Friday that all in-person activities will be prohibited in team facilities Monday and Tuesday in response to rising coronavirus cases and Thanksgiving gatherings. Teams’ operations on those days must be virtual. Teams playing Monday and Tuesday are exempt.

The Ravens-Steelers game originally was scheduled for Thanksgiving night. The league announced Wednesday that the game was being delayed until Sunday at 1:15 p.m. Now, with the outbreak on the Ravens continuing, the game has been pushed back a second time.

This would be the second Tuesday game this season for the NFL. The league had Tennessee play a Tuesday game in October because of an outbreak on the Titans. That was only the second Tuesday NFL game in 74 years.

The Ravens had one positive test Friday by a player on the practice squad, according to a person familiar with the results. The team and the NFL could only hope that was a signal the outbreak was easing.

Approximately 13 Ravens players, including star quarterback Lamar Jackson, and at least seven staff members tested positive for the coronavirus in recent days. Positive test results for four Ravens players were returned late Thursday, according to a person familiar with the results. The positive test by Jackson, the NFL’s reigning MVP, was confirmed by another person close to the situation.

The Steelers, the NFL’s only unbeaten team at 10-0, announced earlier that they were canceling Friday’s practice while they awaited the league’s decision on the game.

“We appreciate our [fans’] patience as we work through the rescheduling of our upcoming game versus the Baltimore Ravens,” the Steelers said in a statement after the game was rescheduled. “Along with the Ravens, we have been working with the league office to ensure the game can be safely played in Week 12. We look forward to a national NBC audience on Tuesday night that will showcase one of the best rivalries in the NFL.”

The Titans and Buffalo Bills played a Tuesday night game Oct. 13 in Week 5. The Titans had 24 members of their organization test positive for the coronavirus in late September and early October. Before that, the NFL had played only one Tuesday game since 1946. That came in 2010, when a December snowstorm in Philadelphia delayed a game between the Eagles and Minnesota Vikings.

“We appreciate the efforts of the NFL and Pittsburgh Steelers throughout this process, while we all work to create an environment that keeps the health and safety of everyone involved at the forefront of each decision,” Ravens Coach John Harbaugh said in a statement released by the team. “Our organization has a plan in place, and we will be prepared to play the Steelers. We thank everyone for their adaptability and look forward to the challenge of facing a very good football team at Heinz Field on Tuesday night.”

With Jackson in isolation after his positive test, backup quarterback Robert Griffin III is line to start for the Ravens. They placed Jackson, fullback Patrick Ricard, defensive tackle Justin Madubuike and long snapper Morgan Cox on their covid-19 reserve list Friday. That list is for players who test positive for the coronavirus or those determined through contact tracing to have been exposed to the virus.

“The word is out, I tested positive yesterday for COVID,” Ricard wrote Friday on Twitter. “I’ll be using this time to rest/recover along [with] my teammates/staff who has been affected by this virus. I appreciate all the love and support. We will come back stronger than ever!”

The Steelers announced Friday that they had placed offensive lineman Jerald Hawkins and defensive linemen Stephon Tuitt and Isaiah Buggs on their covid-19 reserve list.

If the game cannot be played Tuesday, the NFL might be forced to add a Week 18 to its regular season. The Ravens-Steelers game otherwise cannot be rescheduled for later in the season, because both teams already have had their bye weeks. League leaders have said they would add an 18th week if all games cannot be played within the current framework.

Commissioner Roger Goodell previously threatened teams with game forfeits or the loss of draft picks for violations of the league’s coronavirus protocols resulting in adjustments to the schedule. The Ravens announced Wednesday that they were disciplining a staff member for actions related to their coronavirus cases.