The injury Pittsburgh Steelers quarterback Ben Roethlisberger suffered to his throwing shoulder Monday night could be pretty significant, one that could take a while to heal, a source close to the team said.
Roethlisberger is "extremely sore" Tuesday morning and "hurting pretty bad," the source said. After getting an MRI Monday night, he went for another MRI Tuesday.
Tomlin then characterized Roethlisberger's injury as a shoulder sprain at his news conference Tuesday.
"Obviously, his injury puts his participation in the questionable category," Tomlin said.
A Steelers source told ESPN that the team's staff was told, "proceed with (backup quarterback Byron (Leftwich). It doesn't look like you're going to have Ben this week. We're looking at next week as a possibility as of right now."
It seemed highly unusual and perhaps an indication of the seriousness of the injury that Roethlisberger went from the stadium to the hospital for an MRI on his right shoulder so late Monday night and remained there past midnight.
A source who was with Roethlisberger on Monday night told ESPN that doctors informed the quarterback they wanted further evaluations and that a complete diagnosis wouldn't be available until later Tuesday.
The Steelers have a short week to prepare for the archrival Baltimore Ravens, their opponents in two of the next three weeks and the AFC North leaders.
The Steelers have two veteran backup quarterbacks in Leftwich and Charlie Batch -- neither of whom has played much recently because of their own injuries and because Roethlisberger has been so durable.
When asked Tuesday how the playbook would change if Leftwich has to start, Tomlin said, "I don't know that it does."
Roethlisberger was sacked by the Chiefs' Justin Houston to end Pittsburgh's first possession of the second half. Roethlisberger finished 9-of-18 for 84 yards and a touchdown for the Steelers, who won their fourth straight game by beating Kansas City 16-13 in overtime to improve to 6-3.
Roethlisberger has been largely injury-free this season in offensive coordinator Todd Haley's system, which requires him to get rid of the ball quickly. Kansas City's secondary, however, shut down Pittsburgh's receivers, and Roethlisberger took a series of hits on a wet night at Heinz Field.
Leftwich replaced Roethlisberger and finished 7-of-14 for 73 yards in the victory. Leftwich managed to lead the Steelers on one scoring drive early in the fourth that gave them a 13-10 lead.
ESPN's Josina Anderson and ESPN AFC North blogger Jamison Hensley contributed to this report. Information from The Associated Press also was used.