Mark Madden: T.J. Watt and Cameron Heyward have played great, but Steelers' defense isn't elite

The Steelers’ “elite” defense crumbles at inopportune times.

Is the defense about the excellence of edge rusher T.J. Watt and defensive end Cameron Heyward, or is that offset by, say, defensive back Arthur Maulet getting beat like a rented mule late in Monday night’s near-loss to Chicago? (A win is a win, but edging the Bears by two provoked relief more than celebration.)

The Steelers defense is too often only as good as its weakest link.

Consider the last three home games:

• The Steelers led Chicago by 14 points in the third quarter, by 10 in the fourth quarter. Yet quarterback Ben Roethlisberger had to pilot a late-game drive to eke out victory.

• The Steelers led Seattle by 10 in the third quarter but needed overtime to win.

• The Steelers led Denver by 18 in the third quarter but allowed two touchdowns in the fourth quarter and needed an end-zone interception on the game’s final play to win by 8.

Chicago, Seattle and Denver don’t have great offenses. (Seattle was without quarterback Russell Wilson.) But the Steelers’ “elite” defense stumbled nonetheless.

Consider the stats:

• The Steelers defense ranks 14th in yards per game, 21st in yards per play. (It ranks eighth in points per game, so perhaps there’s a “bend, don’t break” thing going on.)

• The Steelers have just eight takeaways, which ranks eighth from bottom.

The Steelers defense just isn’t elite. It’s average. An elite defense has better numbers. An elite defense doesn’t fritter away second-half leads on a regular basis.

How will the defense cope when it faces a good offense and standout quarterbacks such as Justin Herbert, Patrick Mahomes and MVP front-runner Lamar Jackson (twice)?

The Steelers will beat Detroit this Sunday to get to 6-3. But they may not be favored in a game for the rest of the season.

The Steelers need better, especially on defense. (The offense is average, as expected.)

The Steelers can’t get better from Watt and Heyward.

Watt was omnipresent Monday: Three sacks, three tackles for loss, three QB hits, one pass batted down. Watt got big money, then became hell-bent to prove he deserves it. That’s refreshing. He’s the best defensive player in football. That’s not up for debate so far this year.

Heyward was very good, too: Three QB hits and an interception.

But that’s the point: Watt and Heyward are killing it consistently, and that defense still isn’t “elite.”

Safety Minkah Fitzpatrick is known for his “ripple effect,” whatever that is. But he has gone 14 games without an interception and has caused just one turnover in that time.

Everybody else on the Steelers defense is nondescript at best. The most disappointing is inside linebacker Devin Bush, a former first-round pick who won’t get paid come contract time. (Fitzpatrick might not, either. Certainly not what he wants.)

The defense is a two-man wrecking crew plus a subpar supporting cast. How far will that get the Steelers, especially when the big kids start showing up at the playground?

The Steelers are decidedly walking a tightrope when it comes to making the playoffs, especially given the difficulty of their schedule and the number of AFC teams in contention for the conference’s seven playoff spots.

Their stars need to win games. That’s what happened Monday.

Their scrubs can’t lose games. That’s what almost happened Monday.

Ray-Ray McCloud had one job when he returned a fourth-quarter punt: Don’t fumble. Execute a fair catch. Let the ball roll dead. Just don’t fumble.

So McCloud fumbled. The Bears picked up the ball and scored a touchdown.

Pressley Harvin averaged just 39.2 yards per punt. That’s utterly unacceptable.

On consecutive plays, Maulet got beat for a total of 55 yards and a touchdown when Chicago scored the go-ahead touchdown with 1:46 remaining.

Watt and Heyward can’t do any better.

The lesser lights must.