News broke early Wednesday morning that Pittsburgh Steelers quarterback Ben Roethlisberger would not play Sunday due to his sprained right shoulder. But that appears to be the least of his worries.

Later, Roethlisberger said he also suffered a dislocated rib in the third quarter of Pittsburgh’s 16-13 overtime win against Kansas City Monday, which is a far bigger concern for team doctors.

According to reports, doctors are concerned the injured rib could hit Roethlisberger’s aorta.

It is a very rare injury, and in some cases a rib dislocation can take up to six weeks to heal, but that doesn’t include prep time and conditioning to return to any sport.

The two-time Super Bowl winner also called the injury very painful, making it hard for him to move at all.

This is a critical part of the season for Pittsburgh, who have ripped off four straight wins, and are a half-game back of the Baltimore Ravens for the AFC North lead with seven games left this season.

Of those seven games, two are against Baltimore while the rest are match-ups with teams currently below .500.

Neither Roethlisberger nor the Steelers have said if his season is done, but Byron Leftwich was named Sunday’s starter when the Ravens invade Heinz Field.

Leftwich did lead the Steelers to a win Monday, going 7-for-14 for 73 yards, but he hasn’t started a game since 2010. Originally a top draft pick for the Jacksonville Jaguars in 2003, the 32-year-old out of Marshall has spent the last three seasons backing up Roethlisberger, making seven appearances.

When he was a full-time starter, Leftwich went 24-20 in four seasons with Jacksonville and threw 51 touchdowns to 36 interceptions.

The Steelers have gone without Roethlisberger several times in the past. In 2010 he was suspended for the first four games of the season, and Pittsburgh went 3-1 in that stretch. Since 2005, the Steelers have a 7-5 record without him, and are 4-1 the last two years according to the Associated Press.