Steelers Head Coach Mike Tomlin announced that quarterback Ben Roethlisberger has suffered a sprain in his right throwing shoulder.
"Obviously, his injury puts his participation in the questionable category," Tomlin said in his Monday morning press conference.
Tomlin wasn't ready to rule out his starter for Sunday's game against the Ravens, however.
Tomlin described Roethlisberger's shoulder injury as a "SC sprain," which is being further evaluated.
The sternoclavicular (SC) joint helps to support the shoulder, linking the bones of the arms and shoulder to the body, according to orthogate.com. It is the connecting point between the sternum and collarbone, and is an uncommon injury.
"Type of shoulder injury that Ben Roethlisberger suffered is said to be extremely painful and can be a long-term ailment," The Baltimore Sun's Aaron Wilson tweeted.
Multiple media outlets have cited sources with different recovery timeframes for Roethlisberger's injury that ranges from returning this Sunday to missing a couple of weeks. The severity of the sprain will be a factor in his recovery time. There are three degrees of shoulder injuries, the first degree is a sprain, the second is a separation and the third is a dislocation.
ESPN sources say Roethlisberger is "extremely sore." They also say he suffered a rib injury on the same play he suffered the shoulder sprain, which came on a sack the third quarter of Monday Night Football by Kansas City's Tamba Hali.
Another Steelers source said the team's staff has been told to proceed with backup quarterback Byron Leftwich and that it doesn't look like they'll have Roethlisberger.
Tomlin said Leftwich will take the first-team snaps in Pittsburgh's shortened week of practice and would start if Roethlisberger doesn't suit up.
But when asked whether he would possibly use Roethlisberger even without practice, Tomlin said he has before. When asked whether the playbook would change if Leftwich starts, Tomlin said, "I don't know that it does."
The Ravens are 4-0 against the Steelers when Roethlisberger has been out, but those wins are by a collective 15 points.
The Ravens have also seen Roethlisberger play through pain before. Roethlisberger's nose was broken during a 2010 game in Baltimore and continued to play.
Ravens safety Bernard Pollard isn't counting Roethlisberger out.
"We all know what kind of competitor he is, so he's going to do everything he can to get back, especially for this game," Pollard said Tuesday afternoon.
"We have to go in with the mindset that he's playing. … I don't think he's going to be stupid with the decision that he makes, but I really truly believe that he's going to do whatever he can to get back out there."
There were some differing opinions about whether the Ravens want to see Roethlisberger on the field Sunday.
"I don't know if he is going to play or not, but he's a good player and I wouldn't mind if he didn't play," defensive end Arthur Jones said.
"I want them at their best so you don't hear all the excuses," nose tackle Terrence Cody said. "I want to play against him so that if I do get my first sack this week, it can be against Big Ben."
Staff Writer Garrett Downing contributed to this report.