The NFL is a no-nonsense league, and Mike Tomlin is a no-nonsense coach.
Whatever inclination Tomlin may have had to convert the Steelers from their traditional 3-4 base defense to a 4-3 in his first season was tempered by the fact that he doesn't have the personnel to pull it off.
But not in 2007, not when the Steelers don't have enough speed-rushing defensive ends and an active, space-eating middle linebacker to do more than experiment with the 4-3.
"Really, I think my philosophy in terms of style of play falls in line with what's been done in Pittsburgh," Tomlin told reporters last week at the owners meetings, when he made it official that the Steelers will stick with the 3-4. "Whether you do it out of a four-man or a three-man line, the attacking personality and mentality is the same."
The Steelers' defense will continue doing what it does best, led by players best suited for the 3-4.
That doesn't mean the Steelers, who retained veteran defensive coordinator Dick LeBeau, won't present 4-3 looks from time to time. Fact is, the Steelers already have.
Last season, when LeBeau moved ends Aaron Smith and Brett Keisel inside and turned outside linebackers Joey Porter and Clark Haggans into defensive ends on passing downs, the Steelers adopted a 4-3.
"Some successful defenses do it week-to-week," Tomlin said. "I think New England's done it for quite some time. Believe me, Dick's played some 4-3 or some four-down (linemen) packages.
"Football is football. I think sometimes X's and O's are overrated. It's about us putting our guys in position to play well."
Bottom line: The Steelers lack the personnel to play 4-3 all the time.
Even if Smith moved to defensive tackle full-time next to Casey Hampton, which he could do with relative ease, that would still leave the Steelers short at defensive end.
Keisel was impressive in his first year as a starting defensive end, but he isn't the prototypical pass rusher (such as Tampa Bay's Simeon Rice and the Colts' Dwight Freeney) needed to make the 4-3 work as an every-down defense.
The Steelers need more pass-rushing ends, or linebackers who can play end, or ends who can play linebacker. They are likely to address those needs in this year's draft.
At linebacker, James Farrior and Larry Foote would be the top candidates to start in the middle. But that would be asking them to play away from their strengths, which is attacking the run and making short drops in the passing game, and forcing them to play more in open spaces and make deeper drops.
Of course, Tomlin was smart enough to hint at the owners meetings that it wouldn't hurt if Steelers opponents were forced to prepare for both the 3-4 and 4-3.
The Steelers could take a page from the Baltimore Ravens, who confused the Steelers when they mixed up their pass-rushing schemes.
Baltimore, which combines elements of the 3-4 and 4-3, had pass rushers coming from everywhere.
Trevor Pryce, who played defensive end on most rushing downs, moved inside against the pass. Sometimes end/outside linebacker Terrell Suggs rushed from the oustide; sometimes he would loop inside. Pryce and Suggs also lined up together.
Just because the Steelers haven't changed their basic defense doesn't mean that Tomlin can't have the best of both worlds: a 3-4 foundation with its fair share of 4-3 looks