No one’s going to confuse the current Pittsburgh Steelers defense with the Steel Curtain. There aren’t any elite playmakers in the secondary, and there isn’t a dominant force like Mean Joe Greene or L.C. Greenwood to get after the quarterback. This year, their leader and most productive pass rusher was the 38-year-old James Harrison, who finished the regular season with a low-but-team-high five sacks.

Instead of leaning on one or two big-name game-changers like Von Miller or Ndamukong Suh, Pittsburgh has relied upon the even play of a bunch of savvy veterans and young, play-with-their-hair-on-fire athletes. It’s taken some scheming, but defensive coordinator Keith Butler has squeezed every drop of production he could out of a group lacking a true superstar. There are no great defenses left in the playoffs, but Butler has at least created a good one by dialing up the blitz.

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For the first half of the season, Pittsburgh struggled to rush the passer, and that lack of a true edge-rushing force was the core issue. Harrison is well past his prime; last year’s first-round pick, Bud Dupree, missed the first 10 games with a groin injury; and Jarvis Jones, Pittsburgh’s first-round pick from 2013, hasn’t shown many signs that he’s developing into a sack maker on the edge. Through eight weeks, Pittsburgh relied mostly on three- and four-man pressure schemes. They blitzed (sent five or more rushers) just 25.7 percent of the time, per Pro Football Focus, and the result was about what you’d expect: The Steelers were dead last in sacks, with just eight.

Butler recognized that three- and four-man rushes just weren’t going to get the job done, and so he started upping the pressure. From Week 9 to their finale against the Browns in Week 17, Pittsburgh racked up an NFL-best 30 sacks, including an eight-sack performance against the Browns in Week 11. The return of Dupree, who had 4.5 sacks in the last four regular-season games, certainly helped, but the biggest change over the back half of the year was that they blitzed on 43 percent of their defensive snaps (third most in the NFL).

Going blitz heavy isn’t new for a team that once earned the nickname “Blitzburgh.” The zone blitz was a staple of former defensive coordinator Dick LeBeau’s arsenal for years. Instead of the traditional idea of a blitz, in which you roll the dice, send the house, and leave just a few defenders in coverage, he’d disguise his intentions prior to the snap. LeBeau would line up six, seven, sometimes eight or nine guys at the line, then send pressure in the form of a linebacker or defensive back from one side while dropping a different defender into the quarterback’s throwing lanes on another. It was a way for the Steelers to create pressure and confuse offensive lines and quarterbacks without sacrificing numbers in pass coverage.

In the second half of the year, Pittsburgh has gotten back to its roots — both with zone and traditional blitzes. Much like LeBeau used to, Butler has begun to confuse opposing offenses with his pre-snap alignments. And he’s exploited the Steelers’ area of strength: While Pittsburgh has no true standout rusher this year, what it does have in spades is pure athleticism in its back seven, and that speed is often the difference between a pressure and a sack. Butler sends big, explosive athletes hurtling toward unprepared backs and tight ends and dares them to figure out how to stop his defenders.

Take Pittsburgh’s Week 15 matchup with the Bengals. Prior to the snap, Pittsburgh lines up with six defenders at or near the line of scrimmage. With four potential rushers on the left, Cincinnati slides protection to that side. Except only three Steelers actually rush from that side, leaving four linemen matched up with three rushers, creating a numerical disadvantage on the other side. Middle linebacker Ryan Shazier then rushes between the right tackle and guard. He draws tight end Tyler Eifert in the hole on a blitz pickup and beats him easily.

Against the Giants in Week 13, Pittsburgh manipulates the New York protection scheme by lining up one defender on each side of center Weston Richburg. Eli Manning barks out orders to protect against that look, which has four defenders over the center, right guard, and right tackle, and just before he’s about to snap the ball, Harrison drops down onto the left edge. By this time, it’s too late for Manning to change the protections again; you can see the quarterback tell Rashad Jennings he’s responsible for Harrison while trying to get the snap off. When the offensive line protects to the right, Harrison comes off the edge to the left and easily beats the hapless running back in pass protection.

The Steelers love to change things up right before the snap, and last week against the Dolphins, they drop safety Mike Mitchell down into the box at the last second and send him off the edge on a blitz. With two defenders running at him, Dolphins tight end MarQueis Gray hesitates. That lets Harrison through the line, and when running back Jay Ajayi is forced to pick him up in the backfield, it leaves Mitchell with a free path to Matt Moore.

It’s not always a linebacker here or a defensive back there. The Steelers also send multiple blitzers at the same gap to overload a protection scheme. Against the Ravens in Week 16, Shazier rushes through the line off center Jeremy Zuttah’s right shoulder, and he is quickly followed by Lawrence Timmons, who fakes as if he is going to follow right through. At the last second, Timmons veers off to the opposite A-gap, leaving rookie running back Kenneth Dixon blocking air. Joe Flacco pays for it.

Against the Colts in Week 12, Pittsburgh brings a pair of defensive backs — William Gay and Sean Davis — off the right side while dropping three of its interior defenders into coverage from the middle. That leaves five Indianapolis offensive linemen blocking three Pittsburgh linemen, and running back Frank Gore is too late to stop Gay, who knifes through to force the fumble.

In its two games so far this postseason, Pittsburgh’s blitz rate has dropped back down to early-season levels (25.8, per Pro Football Focus), but that’s likely more of an indication of the quarterbacks they’ve faced than a wholesale change in philosophy. They’ll have a choice to make this week against Tom Brady, though: Be content to rush three and four at an elite passer and hope for the best? Or go at him fast and furious, hope to get him off his spot, hit him, and force him to make mistakes?

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The bad news for Pittsburgh, of course, is that it’s a Catch-22. This year, Brady has recorded a 67 percent completion rate, 8.1 yards per attempt, 14 touchdowns, two interceptions, and a 104 passer rating against four or fewer rushers, per Pro Football Focus. But he’s also been a blitz killer: Against five or more pass rushers, he’s completed 66 percent of his passes at 8.5 yards per attempt and has 14 touchdowns and no picks for a 131.4 rating.

Even with a Pittsburgh defense that’s heated up over the past two months, no one’s expecting this AFC championship game to be a defensive slugfest. With two great offenses trading blows in what’s likely to be a high-scoring barnburner, it might come down to which defense can make just one more stop, or create one more turnover than the other. With no big-time edge rusher to lean on to get to Brady in standard three- or four-man rushes, we’re likely to see Butler and the Steelers go all out and send pressure from all angles in hopes of getting the Patriots signal-caller on his back and getting the ball out. If they can do that just once or twice, it could give Pittsburgh enough of an edge to get to Houston. If not, Brady will just sit back in the pocket and pick them apart.