Each player has been placed on the reserve/COVID-19 list.
It's a major blow to the Ravens' backfield just days before Thursday night's game against the undefeated Pittsburgh Steelers.
Gus Edwards is the only available running back on the Ravens' roster who has had any carries this season. Justice Hill, a little-used 2019 fourth-round pick, will be Baltimore's top backup, and practice squad player Ty'Son Williams could get elevated.
Contact tracing is complete and the only other player going on the reserve/COVID-19 list as a close contact is nose tackle Brandon Williams, who will have to quarantine for five days. Two other staff members -- not part of the coaching staff -- also tested positive, but no other players did, according to Harbaugh.
The coach said Thursday's game will be played as scheduled.
"We're just carrying forward with our normal schedule at this point," Harbaugh said. "We're working hard in getting ready for our big challenge against the undefeated Steelers."
Losing Dobbins comes at a time when the Ravens were just starting to lean on the rookie second-round pick as their feature back. In Sunday's 30-24 overtime loss to the Titans, Dobbins tied a career high with 15 carries, producing 70 yards and a touchdown.
Ingram, a Pro Bowl player a year ago, has been gradually getting phased out of the offense. He was limited to six snaps Sunday, the fewest of four Baltimore running backs.
"Sad news to hear about that," tight end Mark Andrews said. "It's a crazy kind of time that we're living in. It kind of goes with this year. There's going to be things thrown at you, and you have to adapt. You look at Gus and Justice. They're incredible athletes and incredible players. They're going to do their job just fine and hold that torch. There's no worries there."
There is a chance Dobbins and Ingram could get cleared before next Thursday night's game against the Dallas Cowboys. They have to quarantine for 10 days.
The Ravens had earlier announced that they closed their facility Monday after learning that multiple members of the organization had tested positive for COVID-19. The facility reopened later Monday and the team planned to conduct a masked walk-through practice.
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 had already been a trying season for the Ravens (6-4), a team that was among the preseason Super Bowl favorites but 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.