Ben Roethlisberger suffered a right shoulder injury Monday night. (Don Wright / AP)

Update: Tomlin says Roethlisberger has shoulder sprain, is questionable

Pittsburgh Steelers quarterback Ben Roethlisberger injured his right shoulder in the team’s 16-13 overtime victory over the Kansas City Chiefs on Monday night.

Just how badly the usually indestructible quarterback is hurt, however, has not yet been revealed.

Sources told Yahoo’s Jason Cole that Roethlisberger suffered a separated shoulder when he was sacked early in the third quarter. He was taken to a Pittsburgh hospital for an MRI and one source told Yahoo that the injury is “unusual.” ESPN’s Adam Schefter reported that the Steelers had been told only that the shoulder is sprained. This morning, ESPN’s Ed Werder reported that the team believes Roethlisberger has a significant injury that will take a while to heal. Werder also reported that Roethlisberger is “extremely sore” this morning and will undergo a second MRI.

Coach Mike Tomlin was typically tight-lipped Monday night.

“I don’t live in the hypothetical world,” Tomlin said. “I wait until I get information and then I respond accordingly to that information.”

Whatever the degree of the injury, the Steelers seem likely to join the growing list of teams who’ve lost starting quarterbacks this week. The Philadelphia Eagles’ Michael Vick, the San Francisco 49ers’ Alex Smith and the Chicago Bears’ Jay Cutler all suffered concussions Sunday.

Roethlisberger, who had completed 9 of 18 passes for 84 yards and a touchdown, was injured when Justin Houston’s helmet rammed into his right shoulder early in the third quarter. Byron Leftwich came in and completed 7 of 14 passes for 73 yards. For now — and possibly significantly longer — he is likely to be the Steelers’ starter. If history is any comfort, the team has survived without Roethlisberger, going 3-1 when he was suspended at the start of the 2010 season. (Back then, Leftwich was a candidate to step in, but he suffered a knee injury in the Steelers’ final preseason game.) But they’ve never done without him for more than four games and there’s a particularly tough stretch looming. The 6-3 Steelers play the Baltimore Ravens twice in the next three games.

Leftwich laughed when he was asked he can lead the Steelers to a Super Bowl win. “We will see,” he said. “We are not going to worry about the Super Bowl right now. We are just going to prepare to try to beat the Baltimore Ravens.”

Roethlisberger has played through pain before, but a shoulder injury is a different matter. A year ago, he hurt his ankle in a Thursday night game against Cleveland and, after limping into the locker room for X-rays, led the Steelers to a victory. He missed only a game last year.

Follow @CindyBoren on Twitter and on Facebook.