By John McMullen, NFL Editor

(Sports Network) - The next chapter in one of the NFL's most heated rivalries lost a little of its luster when Pittsburgh quarterback Ben Roethlisberger went down with shoulder and rib injuries.

Veteran Byron Leftwich will now start at quarterback in the Steelers' key AFC North divisional matchup against the first place Baltimore Ravens.

That doesn't bode well for Pittsburgh, which is 0-4 against the Ravens without Roethlisberger ever since the two-time Super Bowl winner entered the NFL in 2004.

The Steelers enter Sunday night's contest trailing Baltimore by one game for the top spot in the division as Leftwich gets set to make his first start since Sept. 27, 2009 when he was with Tampa Bay.

The veteran Marshall product replaced Roethlisberger in the third quarter of the Steelers' 16-13 overtime victory over the Chiefs on Monday after Big Ben sprained the sternoclavicular joint in his right shoulder. Leftwich finished with pedestrian numbers, completing 7- of-14 passes for 73 yards, but stayed away from the big mistake as he steered Pittsburgh to the win.

A further examination of Roethlisberger revealed he also suffered a dislocation of his first rib, a far more serious problem which could puncture his aorta if the rib moves a certain way when hit.

The two-time Pro Bowl selection could conceivably be out for the rest of the season especially if the Steelers don't extend things by making the playoffs.

"I don't think so. I don't know, though, but I'm not a medical expert," Roethlisberger said when asked if his injuries could cost him the rest of the year. "I just know I'm going to do what I can to get back."

Shaun Suisham finished things on Monday for the Steelers by booting a 23-yard field goal less than a minute into overtime.

Chiefs kicker Ryan Succop had sent the game into an extra session with a 46- yard field goal as time expired in regulation before Kansas City got the first possession of overtime. It wouldn't last long however, as Matt Cassel was intercepted by Lawrence Timmons on the second play from scrimmage.

Timmons returned the pick 23 yards to the Kansas City 5-yard line and Suisham trotted out on the next play for the game-winning gimmee.

"The guys made the necessary plays to get out of the stadium with the win," Steelers coach Mike Tomlin said. "Big time kudos to all the people that made the plays, particularly Lawrence Timmons, what a big play there for us in overtime."

"We just stayed positive," added Timmons. "It's easy to get down, but we are not like that. We stand up and face adversity."

Jonathan Dwyer finished with 56 yards rushing on 19 carries to help the Steelers earn their fourth straight victory and improve to 4-0 in Western Pennsylvania this season.

The Ravens, meanwhile, kept chugging along last Sunday, dismantling the Oakland Raiders 55-20 at M&T Bank Stadium. Joe Flacco threw for 341 yards, three touchdowns and one interception on 21-of-33 passing in that one.

Torrey Smith caught two touchdown passes for a total of 67 yards and Dennis Pitta added five catches for 67 yards and a score for the Ravens, who established a new franchise record for most points in one game and won their 15th consecutive regular- season game in the Charm City.

"Obviously, we had success," said Flacco. "We ran the game plan and it worked well. We stuck with it. We scored points early and continued to score."

Ray Rice ran for 35 yards and a score on 13 carries and Jacoby Jones chipped in with a 105-yard kickoff return for a score in Baltimore's second straight win. Jones became the first player in NFL history with two career 105-plus yard kick-return touchdowns after previously tying the NFL record with a 108- yard kick-return touchdown in Week 6 against Dallas.

"That was a heck of a team victory in all three phases of the game," Ravens coach John Harbaugh said. "I was really pleased with the way we played and the way we finished."

Pittsburgh still leads the all-time series with Baltimore 18-14 but the Ravens have won four of the past six, including last year's bout in the Steel City, a 23-20 thriller won when Flacco hooked up with Smith on a 26-yard touchdown pass with just eight seconds left.

WHAT TO WATCH FOR

The Steelers had more passing yards than the Chiefs on Monday, the 16th straight home game in which they have had more than their opponents, matching the 2000-01 "Greatest Show on Turf" St. Louis Rams for the longest streak in NFL history.

That could be difficult to extend this week without Roethlisberger but there are worse options for Pittsburgh than Leftwich, a veteran who will not be overwhelmed by the moment. The seventh overall pick by the Jacksonville Jaguars in the 2003 draft, Leftwich has a 24-25 career record as a starter while completing 58.2 percent of his passes for 10,333 yards with 58 touchdowns and 41 interceptions.

"Byron is a great player. He's been doing this for a long time," said Roethlisberger. "I know he's going to go out there and give it his all."

Leftwich admitted to experiencing some rust against the Chiefs and should be more equipped to handle things on Sunday after a week of repetitions with the first team offense.

"We got a lot of ball in front of us this week," Tomlin said. "If (Leftwich) is the guy, he'll get a great opportunity to prepare and we'll expect him to play winning football."

Without Roethlisberger, the Steelers will likely rely on their running game to an even higher degree, which could be troublesome considering Dwyer and Isaac Redman combined for just 77 yards on 27 carries against Kansas City. The Pittsburgh ground game did average over 140 yards and 4.5 per carry in the team's previous three games, however.

Redman also told the Pittsburgh Post Gazette that it "looks like" Rashard Mendenhall will return from an Achilles injury to start. Mendenhall, who once ran for 1,273 yards back in 2010, missed the first three games of this season as he continued to recover from a torn ACL and missed the previous four with the Achilles injury.

While Baltimore has been successful as usual this season, it has been doing things in a far different manner. The Ravens typically sport one of the NFL's toughest defenses but currently rank 27th in the league in yards allowed (390.2) and 26th against the pass (258.2). The injuries to All-Pro middle linebacker Ray Lewis (triceps) and top cornerback Lardarius Webb (ACL) have obviously taken a toll. The embattled group is expected to get a boost with the return of defensive tackle Haloti Ngata (shoulder), who sat out against the Raiders.

Defensively the Steelers lead the NFL in both overall defense (265.7 yards a game) and pass defense 171.1 ypg) despite being without star safety Troy Polamalu (calf) for the majority of the season. Polamalu remains doubtful for Sunday but fellow safety Ryan Clark, who suffered his second concussion in three games against Kansas City, should be ready to go.

OVERALL ANALYSIS

The Ravens come in having won 11 straight versus AFC North foes and are 4-0 versus the Steelers when Roethlisberger has been unable to go. Meanwhile, despite the problems on defense Baltimore is third in the AFC with a plus-nine turnover ratio.

About the only thing the Steelers have working in their favor is Heinz Field but that won't be enough to even things in the division without Big Ben.

Sports Network Predicted Outcome: Ravens 23, Steelers 13