PITTSBURGH — Charlie Batch played well enough on two good ankles to keep Ben Roethlisberger from having to play on a bad one.
The veteran backup quarterback played efficiently if not spectacularly in place of the injured Roethlisberger, passing for 208 yards as the Pittsburgh Steelers crushed lifeless St. Louis 27-0 on Saturday.
Rashard Mendenhall ran for 116 yards and a touchdown, and John Clay and Ike Redman also scored for the Steelers (11-4), who kept their hopes of an AFC North title alive even with Roethlisberger's sprained left ankle forcing him to watch the game from the sideline as the team's third quarterback.
Pittsburgh hardly needed him. The defense had little trouble dominating the NFL's lowest-scoring offense.
St. Louis (2-13) managed just 232 yards while getting shut out for the second time this month. Steven Jackson rushed for 103 yards to top 1,000 for the seventh straight season, but backup quarterback Kellen Clemens sputtered in place of the injured Sam Bradford. The Rams lost their sixth straight to drop into a tie for the league's worst record with a week to go in the season.
Clemens, signed less than three weeks ago, completed 9 of 24 passes for 91 yards. He didn't turn it over, but he couldn't make anything happen against the league's top-ranked defense.
Batch, making just his seventh start since 2001, had no such issues.
The 37-year-old improved to 5-2 as a starter with his hometown team, his only hiccup coming on a second-quarter interception when intended receiver Antonio Brown slipped while coming out of his cut.
The crowd chanting "Charlie! Charlie!" at times, Batch completed 15 of 22 passes and even got the ball downfield on a couple of occasions, including a 46-yard pass to Mike Wallace in the fourth quarter that set up Mendenhall's 1-yard plunge that put Pittsburgh up 20-0.
It was more than enough cushion for a defense that looked just fine even without injured outside linebacker LaMarr Woodley, who continues to nurse a strained right hamstring. James Harrison collected his ninth sack of the season in his return from a one-game suspension for a series of illegal hits, and Pittsburgh never let St. Louis get within 10 yards of the end zone.
The Rams were able to move the ball at times, mainly on the legs of Jackson, one of the few bright spots in a miserable season that has left coach Steve Spagnuolo's future very much in doubt. A year after finishing 7-9, St. Louis again finds itself in the mix for the top overall pick.
The Rams tried, at least for a while. Yet each time St. Louis appeared ready to make things interesting, it would find a way to let the Steelers off the hook. The Rams opened up the playbook in the second quarter, with punter Donnie Jones pulling the ball down and looking to pass on a fake punt. Pittsburgh covered it well and Jones took off, only to be tackled a yard short of the first down.
St. Louis put together a steady drive late in the first half but got conservative after moving into Pittsburgh territory, milking the clock so Josh Brown could attempt a 52-yard field goal at a stadium where 22-yarders aren't a given. The ball sailed wide left, and Brown later missed wide right in the fourth quarter with the game still somewhat competitive.
Emphasis on the somewhat.
The Steelers were never in any real danger as Mendenhall found plenty of room to maneuver against the NFL's worst run defense, while Batch extended a couple of plays with his feet to keep drives alive.
Mendenhall's 52-yard run in the second quarter set up Clay's first NFL carry, a 10-yard burst over right tackle that gave Pittsburgh a 10-0 second-quarter lead.
Shaun Suisham drilled a field goal in the third quarter to put the Steelers up 13-0. After Brown missed his second kick of the day early in the fourth, Pittsburgh put it away with a pair of easy touchdown drives.
The Steelers can win the AFC North next week with a win over Cleveland and a Cincinnati victory over Baltimore.