When he was hired by the Steelers, Mike Tomlin was a guy who coordinated a 4-3 defense in Minnesota on his way to a team that had long favored the 3-4 alignment.
That proved not to be an issue in 2007. Tomlin perceives it as even less of an issue today.
"I think in today's NFL it's about situational football and what offenses do, and how many receivers they have on the field," Tomlin said this week at the NFL Owners' Meeting. "Oftentimes we spend a lot of time in sub-package football, whether you are a 3-4 or a 4-3 (front).
"In today's NFL, most times you have five or six defensive backs on the field. And I really think that is the discussion as opposed to whether you are a 3-4 or a 4-3, to be honest with you."
The Steelers still favor the 3-4 look. But the focal point of their defensive philosophy is much more about generating pressure than it is about where that pressure might be coming from.
"We have to be multiple," Tomlin said. "We have to be capable of providing pressure, but more important than that you have to be able to provide pressure with four or fewer (pass rushers). I think that's what gives you the flexibility to be something to deal with."
There was a time when teams relied primarily on a relatively basic, two-deep safeties alignment in the secondary, a coverage known as the "Tampa 2" based on how popular the concept was with its originator, former Tampa Bay Buccaneers Coach Tony Dungy.
And the "Cover 2" or "Tampa 2" look still has its place in the game, Tomlin maintained.
But extra-defensive backs packages that counter how offenses are deployed today are an absolute prerequisite for defensive success.
"Obviously, I am a fundamentalist," Tomlin said. "And that's a very fundamental defense, so I would never say it has run its course. But I really think the emphasis in today's NFL is about sub-package football because of the number of multiple-receiver sets that you see. Significant discussion regarding schematics revolves around that."
It also revolves around what the safeties are capable of doing. At least, it does in Pittsburgh.
"I think a component of this defense is great safety play," Tomlin said. "It's something that I've been around since the early days for me as a professional. I've been around guys like (former Buccaneers safeties) John Lynch and Dexter Jackson.
"And rightfully so, I think that if you're interested in playing good defense, you better have guys at the safety position who can insert themselves vs. the run and can be what they need to be in the passing game."
Cornerbacks are likewise critical in Tomlin's estimation, and you better have plenty of them.
"Man, you better have four," he insisted. "You know what I mean? Yeah, that's today's NFL."