At 6 feet 5 inches and 241 pounds, Roethlisberger is better able to withstand blows than the stringy sorts, but he has sometimes seemed less nimble when he scrambles out of the pocket — a hallmark of his playing style — than he was earlier in his career. He is far from fragile, though. Even as he has absorbed the sack barrage in the last three seasons, he has missed only two starts — and one of them came after an appendectomy less than a week before the 2006 season opener.  Although Roethlisberger said he passed a battery of concussion tests, and he and Steelers coaches said he was fine in practice all week, experts in brain trauma say that each concussion a person sustains — this was at least Roethlisberger’s third in two and a half years — makes him susceptible to more. For a quarterback who is hit as often as Roethlisberger is, more injuries of all kinds seem inevitable. It is a Faustian bargain Roethlisberger and the Steelers are willing to make for now.  “I think that’s part of the job,” the offensive coordinator Bruce Arians said. “The job description is you’re going to get hit back there some. Hopefully not to the head. He’s a scrambler; he’s a riverboat gambler. You’re never going to take that away from him; that’s what makes him great. With that come more hits than a normal quarterback is going to take. He’ll take more hits than Peyton Manning because Peyton will just throw it away. He’ll go out and make a play. Sometimes, you get sacked on that. But there’s a lot of big plays on film from that, also.”  The Steelers have needed each of those big plays this season. Counter to a burnished team image that dovetails nicely with the gritty, honest-day’s-work reputation of their hometown, the Steelers became increasingly one-dimensional this season, the passing game given pre-eminence as the running game, especially the power run, struggled.  The franchise that gave the N.F.L. Franco Harris and Rocky Bleier will never be called a finesse team. But with the lead back, Willie Parker, missing five games with a knee injury, the rookie Rashard Mendenhall lost for the season with a shoulder fracture after only four games and the offensive line losing two starters to injury (and guard Alan Faneca to the Jets in the off-season), rushes accounted for only 45.3 percent of the Steelers’ offensive plays this season. That ranked them 13th in the N.F.L., according to Stats LLC, and is down from 51.1 percent last season (ranked third) and 57.2 percent (first) in 2005, their most recent Super Bowl championship season.  Since 1992, the former coach Bill Cowher’s first year, the Steelers have been in the top five of rushing attempts for all but four seasons: 1998 (8th), 2003 (tied for 16th), 2006 (tied for 14th) and 2008 (9th). The Steelers were .500 or below in three of those seasons. The exception is 2008. And this year, the Steelers averaged just 105.6 yards rushing, the lowest average of any previous playoff team in Steelers history.  That has led to a minor flurry of complaining about play calling. Parker expressed dissatisfaction last month with the style of runs being called — he and much of the maligned offensive line want more classic I-formation with a fullback, which had success in the finale against the Cleveland Browns.  Coach Mike Tomlin pointedly noted that Parker, known as Fast Willie, was not complaining last season when he led the league in rushing until being injured in the Steelers’ next-to-last game. The Steelers do most of their running without a fullback, and when they played the Chargers this season, they ran largely out of the spread formation. Parker had 115 yards in that game.  “If I was on the defensive side of the ball, I wouldn’t respect the running game because we haven’t been that successful this year,” Parker said. “We’ve never been viewed as one-dimensional — we have, but it was a running team. If you look at it now, we’re not a running team no more. Are we a passing team? You could say we’re a passing team.”  That creates a vicious cycle for Roethlisberger: a defense that is unafraid of the running game can rush the quarterback with abandon, and the lack of a significant running threat means the play-action fake, the bedrock of nearly every productive passing attack, is not effective. The fallout: the teams that gave the Steelers trouble this season had outstanding pass rushes. The Eagles sacked Roethlisberger eight times, the Giants and the Tennessee Titans five each. Even Indianapolis, not exactly a defensive powerhouse, got Roethlisberger twice. Those are the four teams the Steelers lost to in the regular season.  When the Steelers and the Chargers played in November (the Steelers won, 11-10), Roethlisberger was sacked four times. The Steelers’ offense dominated, anyway, but they did not score touchdowns.  The Chargers have turned up their pressure since that game under the defensive coordinator Ron Rivera, who took over midway through the season. San Diego forced Manning out of his comfort zone in the wild-card game last weekend. To keep Roethlisberger upright — for this game, this postseason and his career — the Steelers know they must at least try to establish their traditional playoff look: 3 yards and a cloud of snow.  “For us to be known as a physical team, it’s hard to be a physical team when you’re passing all the time,” receiver Hines Ward said. “We can’t be 40-20 pass-to-run ratio.”  The answer for the Steelers may be standing next to Roethlisberger on the field Sunday after all. Bettis is taking part in the coin toss.  A version of this article appears in print on , on Page SP1 of the New York edition with the headline: Pass-First Offense Takes Its Toll on Roethlisberger. Order Reprints| Today's Paper|Subscribe
Ben Roethlisberger has taken a beating this season, just as the passing game has become more valuable to the Steelers than ever before.