PITTSBURGH -- Defensive tackle Javon Hargrave is listed at 305 pounds, so he's proud of his 4.93-second 40 time from the 2016 NFL scouting combine.

Behind him, he'll have at least five Pittsburgh Steelers defenders who run a sub-4.5 40-yard dash.

"Everybody [on this defense] can run," Hargrave said. "There are a lot of fast offensive guys, so we need speed to chase them down."

The days of the Steel Curtain are over. This is the Steel Pursuit.

The Steelers still cling to traditional pillars such as stopping the run on early downs and all 11 men to the ball, but they also believe in hybrid weapons and personnel packages galore and speed everywhere.

Just look at the past two first-round draft picks. Safety Terrell Edmunds is fairly big for his position at 6-foot-1 and 217 pounds but has range and open-field speed. Linebacker Devin Bush is fairly small for his position at 5-foot-11, 234 pounds but can cover just about every blade of grass on Sundays with quickness, angles and straight-line bolts.

Throw in former combine freak Bud Dupree at edge rusher, defensive ends who never give up on a play (Cameron Heyward and Stephon Tuitt) and multiple capable parts elsewhere, and the Steelers might just use defense to adequately replace departed offensive stars Le'Veon Bell and Antonio Brown.

Even quarterback Ben Roethlisberger has noticed the defense is "flying around."

"I know we’ve said things like that in the past, but to see how fast guys are moving, covering, secondary guys to linebackers and D-line, it felt like even on a simple run play, all 11 guys on defense were getting to a run or a receiver," Roethlisberger said. "It feels like there is more energy over there."

The Steelers have been hard to figure out the past five years. They measure up in many statistical categories. Last year's group ranked sixth in total defense and first in sacks with 52. Over the past two seasons, no team has sacked quarterbacks more than Pittsburgh's 108.

Then there are days when Pittsburgh can't get a stop. Losing 45-42 in the 2018 divisional playoff against a pass-allergic Jacksonville offense was a low. The 2018 Steelers lost three games by three points apiece over the final five weeks of the season, and in each game they allowed a score in the final two minutes.

To improve the secondary, the Steelers' scheme is mixing nickel and dime more than a mall fountain. Pittsburgh often has six defensive backs on the field, usually either Cam Sutton or former first-round pick Artie Burns supporting slot corner Mike Hilton, free-agent pickup Steven Nelson and veteran Joe Haden.

Tuitt believes the Steelers have a top defense but must "tweak some things" to get over the top: get to the quarterback, create turnovers.

Pittsburgh was good in the first category but tied for 29th in turnovers with 15.

"Probably a step or two here or there, an angle or two better [will help]," Tuitt said. "I think we have a lot of older guys to understand what it will take. Now, it's instinct.

"We have a lot of guys with a fire sparked to prove some things."

Like Hargrave, who enters a contract year after a 6.5-sack season and believes Pittsburgh's defensive line is "the best in the league -- that's how we come out with our mindset."

If that declaration proves true, the Steelers will need corners to capitalize on up-front pressure by crashing passing lanes. Nelson likes the Steelers' chances, thanks to the "very unique" defensive setup.

"One thing I've learned, we have a lot of guys who can play different positions," said Nelson, who can play in the slot or the outside. "Utilizing that versatility is going to be good."