PITTSBURGH -- The Pittsburgh Steelers ran their winning streak to four games Monday night, but it wasn't pretty, and it might have been costly.
The Steelers edged the hapless Kansas City Chiefs 16-13 when Shaun Suisham kicked a 23-yard field goal with 14:05 left in overtime at Heinz Field.
Steelers quarterback Ben Roethlisberger wasn't part of the winning finish. He hurt his right shoulder in the opening minute of the third quarter when he was sacked by Justin Houston.
Roethlisberger did not return to the game, and when he left the stadium to have X-rays, televisions cameras showed that his shoulder was in a sling.
Steelers All-Pro free safety Ryan Clark also left the game in the waning moments of regulation with a possible concussion.
"Obviously, those two men are critical to our effort here moving ahead," Steelers coach Mike Tomlin said.
Steelers linebacker Lawrence Timmons intercepted a Matt Cassel pass on the second play of overtime and returned it 23 yards to the Kansas City 5. Pittsburgh (6-3) wasted no time bringing in Suisham for the game-winning kick.
"He threw it my way, and I just tried to catch it," Timmons said. "The defensive line really made the play happen. They put a lot of pressure on him and forced him to rush his throw."
Kansas City's Ryan Succop kicked a 46-yard field goal as time expired in regulation to tie the game at 13-13 and force overtime. The Chiefs (1-8) drove eight plays and 52 yards in 1:52 for the field goal.
Cassel, starting for a second straight week with Brady Quinn out due to a concussion, kept the Chiefs' hope alive when he completed a 27-yard pass to Dwayne Bowe to the Steelers' 28 on fourth-and-15. That gave Succop to opportunity to tie the game after he missed a 32-yard attempt wide right in the third quarter.
The score was 10-10 when Roethlisberger got hurt. Suisham kicked a 31-yard field goal with 12:41 remaining to put Pittsburgh in front 13-10.
The Chiefs lost their sixth consecutive game but left Heinz Field feeling good about their effort.
"This is the best game we've played so far this year collectively, without a doubt," Cassel said. "I think we played well in all phases. We just played football in which we complemented each other, and that was the first time that we played well together this year."
Roethlisberger completed nine of 18 passes for 84 yards and a touchdown. Backup Byron Leftwich went 7-for-14 for 73 yards.
It was Leftwich's first action since the final game of the 2010 regular season, when he mopped up in a 41-9 rout of the Cleveland Browns. He missed all of last season after suffering a broken elbow in the preseason.
Leftwich has not started since 2009, when he went 0-3 in place of Roethlisberger. He could be in the lineup Sunday night for a pivotal AFC North game against the first-place Baltimore Ravens (7-2).
"If I have to start next week, I'm sure I'll remember what to do," Leftwich said. "I've been in the league 10 years, so I've got a pretty good idea of what I need to do. The good thing is that if I do start, I won't go in completely cold. Getting a chance to play tonight will help. I was able to brush off some of the rust."
Kansas City's Jamaal Charles rushed for 100 yards and one touchdown on 23 carries on a rainy night. Cassel completed 11 of 26 passes for 154 yards with one interception.
Pittsburgh overcame a 10-0 deficit to forge a 10-10 halftime tie. Mike Wallace made a tumbling, one-handed catch in the end zone of Roethlisberger's 7-yard pass with 3:16 left in the second quarter to even the score.
For the first time all season, Kansas City took a lead in regulation as it built a 10-0 advantage.
Charles opened the scoring when ran 12 yards for a touchdown with 8:42 left in the first quarter. The run capped a four-play, 70-yard drive that was highlighted by Cassel's 38-yard pass to Tony Moeaki.
The Chiefs pushed the lead to 10-0 on Succop's 22-yard field goal that came 40 seconds into the second quarter. The kick came three plays after Allen Bailey recovered a fumble by Steelers running back Isaac Redman at the Pittsburgh 11-yard line.
The Steelers cut the deficit to 10-3 on Suisham's 35-yard field goal with 5:38 left in the half.
The last NFL team to play the first eight games of a season without a lead was the 1929 Buffalo Bisons. The only time the Chiefs were ahead this year before Monday was when Succop kicked a field goal in overtime to beat the New Orleans Saints 27-24 on Sept. 23.
The Chiefs, as has too often been the case this season, didn't make quite enough plays Monday.