For most football fans, about the only interesting question left to answer in the second half of the 2007 season is whether there’s a team out there capable of stepping it up to the level of the New England Patriots or the Indianapolis Colts. That team, if it exists, almost certainly isn’t going to come from the NFC, as the Pats’ 48–27 victory over the Dallas Cowboys on October 14 proved.

The Pittsburgh Steelers’ 38–7 dismantling of the Baltimore Ravens last Monday night may have sent a message to New England and to Indianapolis: There’s another serious contender in the league, and it’s in your own conference. The Ravens aren’t that good. They went into the game at just 4–3, but they did have serious playoff hopes, and they were, after all, picked by ESPN the Magazine to win the AFC this year. The thoroughness with which the Ravens were thrashed was reminiscent of the beatings the Patriots have put on their foes this season. Discarding their customary cut-and-slash tactics in the red zone, Pittsburgh offensive coordinator Bruce Arians turned quarterback Ben Roethlisberger loose for a franchise record five touchdown passes and the most points the Steelers have scored this season.

The old saw in pro football is that offense sells tickets but defense wins championships, but nobody really believes that. Since 1978 when the passing rules were liberalized, NFL football has merely been a series of arguments among top coaches on how to make the passing game more explosive. Everybody wants a great defense, of course, but as the Chicago Bears proved in last year’s Super Bowl, a great defensive team with a bad passing attack is like a modern army in a desert war with a second-rate air force.

For what it’s worth, and it’s still certainly worth something, the Steelers currently have the NFL’s best defense, better than the Patriots or Colts, leading the league in fewest points allowed (12.3), fewest yards allowed per game (237.8), and fewest passing yards allowed per game (161.8). They are tied for second in the league in sacks (25). So far, the Steelers’ 2007 defense is on track to be at least as good as the Super Bowl-winning unit of two seasons ago.

But the Steelers’ chances this year depend mostly on Roethlisberger. Age 25 and standing 6 feet 5 inches tall and weighing about 240 pounds, Roethlisberger may be the best young quarterback in the NFL. He may prove to be one of the best young quarterbacks in NFL history. That he isn’t recognized as such is probably due to several factors, one being his dreadful performance against the Seattle Seahawks in the 2006 Super Bowl (despite which the Steelers still won) and his ditzy, much publicized motorcycle antics of 2006, on which many blamed his league-worst 23 interceptions and the Steelers’ 8–8 record last year. (To be fair, an appendectomy caused him to miss the season opener and a load of practice time; his first three starts resulted in three losses, no TD passes, and seven interceptions.) But Roethlisberger swears that his Mad Max years are behind him, and he’s headed for the best season of his four in professional football.

This may be true, but the Steelers under new head coach Mike Tomlin still seem reluctant to let Roethlisberger build up to a full head of steam. If you tell someone that Roethlisberger, since 2004, has been a more effective quarterback than either Tom Brady or Peyton Manning, they’ll probably look at you cross-eyed. But the operative word is effective, not prolific. The key stat to measuring passing effectiveness is yards per throw — how far a quarterback moves the ball downfield, on average, when he puts it in the air. Here’s a comparison of Roethlisberger’s performance over the last four seasons with the performances of both Manning and Brady over the same period:

Big Ben averaged a phenomenal 8.8 yards a throw in his first two seasons in the NFL and is headed for his third season in four years of eight-plus yards per throw. No one in the modern era — not Johnny Unitas, not Dan Marino, not Joe Montana, and not Brady or Manning — has approached such efficiency. Yet Roethlisberger has never been allowed to throw as many passes per game as his chief rivals. Even against Baltimore on Monday night, he threw just 16 passes (completing 13 for 209 yards) to get his five TDs.

The Steelers, from the coming of Chuck Noll in 1969 through the reign of Bill Cowher, which began in 1992 and ended last year, has always had a reputation as a ball-control offensive team. But after two inexplicable losses this season — 14–21 to Arizona in their fourth game and 28–31 to Denver in their seventh — it’s time for Pittsburgh to stop being complacent about how much they’ve turned their team around from last season and start acting like a Super Bowl contender.

After this Sunday’s home game with the Cleveland Browns (a team they beat 34–7 on opening day), the Steelers have only one tough game remaining all season: December 9 at New England. If the Patriots should slip and lose just one game before the start of the playoffs, the Pittsburgh-New England game could loom large in determining the home field advantage for the playoffs and thus the AFC Championship.

The Steelers may have the best defense in the NFL, and they may also have the best quarterback. It’s about time they found out.

Mr. Barra is the author of “The Last Coach: A Life of Paul ‘Bear’ Bryant.”