Nasty up front - Part one: DL has the potential to restore the Steelers dominant rushing D

What stands almost 39 feet tall and weighs nearly a ton?

The six guys I figure are probably locks to make the Steelers' 53-man roster on the defensive line, that's what.  Or, should I say, "who."

Those six are Cameron Heyward, Steve McLendon, Stephon Tuitt, Daniel McCullers, Clifton Geathers and L.T. Walton. Of that list, Walton may be the shakiest of them all, but it's probably him or Ethan Hemer.  Either way, that's a whole lot of human.

It's an average of nearly 318 pounds apiece, and right about 6 feet, five inches in height. And, to hear them and their position coach, John Mitchell, talk during Organized Team Activities, that amounts to six rather large chips on their shoulders, too.

Last year, the Steelers' defense continued a downward trend.  It was just a few short years ago that gaining 100 yards rushing against a Pittsburgh defense was about as common as an eight-legged cat appearing in the Rockettes' famed kick line. Lately, though, it seems those are about the odds of not going over the century mark on the ground.

So, the team has gone about collecting the people to fix the problem, and they just may have found it in big, tenacious, athletic bodies up front.

Heyward has become a leader of the entire defense, and he plays with the calculated strength of Aaron Smith and the motor of Brett Keisel. McLendon may unfairly be compared to former nose tackle Casey Hampton, but he has done well in his own right and is one of the strongest players on the team. The injury bug has bitten him a bit too often, but when he plays you rarely hear his name.  As a nose tackle, that's usually a good thing.

Tuitt, though, will be the key cog. His ability to continue his late-season growth from 2014 will be the lynchpin in the Steelers' 2015 rushing defense: if he holds, they roll.  If he fails, the wheels come off. Lest we forget, he was just 20 years old in 2014. While many players are playing their junior years in college at that age, he was a first-round talent who became a young, raw, second-round steal for Pittsburgh. It justifiably took a while, but we saw him emerge against the Chiefs, athletically running down and stripping the ball from Jamaal Charles after a catch and getting his first career sack.

For all the strengths of the starters, however, the backups' roles may be even more critical. Geathers was re-signed in the off-season at the behest of Mitchell. Take a quick glance at him now and you can see why: at a mountainous 6'8" and 300 lean pounds, he's an imposing sight. His length, strength and experience will be an asset for the two young guys who will also serve as backups along the line, and he has a mean streak to go along with the chip he carries.

Across the line from Geathers will likely be either Walton -- a sixth-round pick in May's NFL Draft -- or one of the last year's practice-squad stashes: Hemer, or Joe Kruger.  Right now, I'm giving the nod to Walton, but it's really a toss-up at this point. Hemer and Kruger are pure athletes, while Walton is bigger and stronger.

Finally, there is McCullers. What he put on tape last year was impressive, promising, and maddening, all at the same time. He proved he can move just about anything that lines up on the other side of the ball, but he struggled to release from blocks and make plays. Fitness had also been a concern, but that seems to be a thing of the past: he is lighter, leaner and stronger, according to his coaches (and the eye test, too), and the few glimpses we have had from OTAs show he is translating his training into improved play.

Conspicuously missing from the list? Cam Thomas, a free-agent signing in 2014. Conspicuous, but not surprising. His play was flat and uninspired, and he is costing the team a lot for a slam-dunk backup. The bottom line is there is too much potential outside of Heyward, McLendon and Tuitt to justify keeping Thomas around as just another warm body. Call it an obvious case of addition by subtraction.

For now, it's all just potential. But, after several years of struggling to stop the run, that much potential finally adds up to a lot of hope.

Not to mention a mountain of nasty, hungry men.