EDEN PRAIRIE, Minn. (AP) True innovation in the NFL can be tough. Successful schemes breed imitations and force opponents to adjust. Eventually, even for the soundest of systems, the code is bound to be cracked.
Consider the case of the ''Tampa 2'' defense.
''You're not going to shock people when you throw out the Tampa 2: `Oh, my gosh. How do we attack this?' Because that's all they've been doing for quite a few years now,'' said Dallas assistant coach Monte Kiffin, who directed and perfected the defense under Tony Dungy with Tampa Bay.
When Minnesota replaced Leslie Frazier with Mike Zimmer as head coach this season, yet another team discarded the Tampa 2 as its basic strategy. The Vikings gave up the most points in the league last year, and some veteran players complained about predictability.
''Sometimes we'd line up and Aaron Rodgers is calling out our defense as we're lining up,'' defensive end Brian Robison said.
The Vikings installed the Tampa 2 in 2006, when Detroit (Rod Marinelli) and Kansas City (Herm Edwards) were also getting it going with new head coaches. Chicago was playing it well under Lovie Smith, as was Tampa Bay with Kiffin, the defensive coordinator. During that pinnacle season, Dungy guided Indianapolis to a Super Bowl victory over Smith's Bears.
Kiffin and Marinelli still teach it with the Cowboys, and Smith and Frazier have returned it to the Buccaneers, but evidence of the Tampa 2's use around the NFL these days is scant.
Ten years ago, this was an ideal base defense.
Teams could rely on a four-man pass rush up front more than blitzing. In turn, outside linebackers and cornerbacks dropped into coverage zones, with the middle linebacker backpedaling into the crease between the safeties to make deep passes difficult. Sure tacklers from the back seven were assigned to gaps in the line for run support, freeing the front four to focus on one each. Scoring against a Tampa 2 was going to require patience.
''We did a lot of things that were simplistic. We never worried about the size. The defense was built on quickness,'' Kiffin said.
Smith, Marinelli and Edwards were Buccaneers assistants in the late 1990s under Dungy and Kiffin, who took the system south after developing it together in Minnesota. The catchy nickname for this derivative of the Cover 2 zone strategy, defined by two safeties splitting the deep halves of the field in pass coverage, stuck during Tampa Bay's time as an NFC power.
The roots, however, traced to Pittsburgh with head coach Chuck Noll and defensive coordinator Bud Carson two decades before that. Dungy was a young defensive back then for the Steelers.
''People identified it with Tampa, but there was nothing different. We didn't make any changes from the 1975 playbook,'' Dungy said. ''There isn't too much new in the game of football that hasn't been done before.''
With tackle Warren Sapp, linebacker Derrick Brooks and safety John Lynch, those Buccaneers teams had quite the backbone.
''You can have the blueprints, but if you don't have the parts they don't work,'' Brooks said. ''Players play the game. Systems don't.''
Seams in the coverage, though, were easier to exploit without Hall of Fame players like Sapp and Brooks defending. Dungy and Edwards moved from the sideline to the TV studio. The increase in three-wide receiver and two-tight end sets, plus elite quarterback play, minimized the effectiveness of the Tampa 2.
Then there was the rule changes designed to stem head and neck injuries, with stiffer penalties for hits on defenseless receivers. Opponents, thus, became more emboldened to run routes across the middle without an enforcer like Lynch waiting to punish them.
''Lynch would knock the hell out of you,'' Sapp said. ''You can't do it anymore. That's the question I have for Lovie. How do you plan on doing what we did to take away the middle of that field?''
Even during the heyday, Tampa 2 teams didn't run it all the time. More like half of the plays, at most. Offenses are too sophisticated to stay the same every snap. Down, distance, time and score dictate calls as much as anything. Smith said he'd like to blitz about one-third of the time this season.
Still, Frazier, eager to work with Pro Bowl tackle Gerald McCoy and linebacker Lavonte David, said he has ''no doubt'' the Tampa 2 is still viable.
''We feel like we have the foundation on this defense to make it work,'' Frazier said.
That's the key, of course.
''It's not about the Xs and Os. It's about the Billys and the Joes. You put great players out there in any defense, it's going to look pretty good,'' said former Cincinnati wide receiver and current NBC analyst Cris Collinsworth, adding: ''I think it all still has a place, but the longer guys get a chance to study the tapes and to see it, the more it has to evolve.''
AP Sports Writers Fred Goodall in Tampa, Florida, and Schuyler Dixon in Irving, Texas, contributed to this report.
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