Mike Zimmer and Leslie Frazier, two men with distinctly different defensive philosophies, collide Sunday in Tampa, Fla., with new teams that are at similar low points best described by Buccaneers coach Lovie Smith.

"It's as simple as this," Smith said. "You have to crawl before you can walk."

Right now, both defenses are doing some crawling and occasionally spitting up on themselves.

Zimmer, who is Frazier's successor as Vikings head coach, has the better defense statistically, ranking 13th in total yards (337.9 per game) and 14th in scoring (22.9), which is 18 spots higher last year's last-place ranking. Yet the sting of last week's defensive collapse came with an all-too-familiar look that was downright routine during the 5-10-1 season that ushered Frazier out of town and into his new job as Smith's defensive coordinator.

Meanwhile, in Tampa, the Bucs had a bye week to get healthy and in sync with Frazier's Tampa 2-based defense, which ranks last in the NFL in total yards (422.8) and points. Tampa Bay's 34 points allowed per game are four more than the Vikings gave up at the bottom of the league in 2013.

Add it all up and, well, you have the NFC's worst record — Tampa Bay's 1-5 — facing a 2-5 Vikings team that's already three games back in the NFC North.

"Everyone would like for everything to be rolling in the right direction and everything working out perfectly initially," Smith said. "But it just doesn't happen that way normally. You have to go through adversity early on, which we've done. But it just makes you stronger."

Defending Tampa 2

Smith and Frazier are two of the staunchest supporters of the Tampa 2 scheme in the NFL today. The no-frills philosophy doesn't offer the popular exotic looks and blitz packages, depending more on a four-man rush with basic but, ideally, well-choreographed zone coverages set behind it. The defense gets its name from the Cover 2 — two deep safeties splitting the field — that former Bucs coach Tony Dungy popularized with Tampa Bay in the 1990s.

"The Tampa 2 is all about the front four getting off the ball, penetrating and playing the run on the way to the quarterback," said Vikings defensive end Corey Wootton, who played the scheme when Smith was the coach of the Chicago Bears. "Here, the primary focus up front is to stop the run on first and second down and then get after people on third down with multiple looks and packages.

"We mix it up more. But there was a time in Chicago when we had a really good defense. I think it depends a lot on your personnel."

The Tampa 2 scheme is designed to take away explosive plays. Ideally, it forces offenses to take more snaps to move the ball, with a core belief being that eventually the offense will make mistakes and turn the ball over.

But in today's NFL, with quarterbacks posting record completion percentages, many critics argue that the scheme is antiquated. The Bucs are supporting that argument with lopsided losses and poor statistics, including an anemic pass rush — 25th in sacks per pass play — that hopes to improve against a Vikings offense that ranks last in sacks per pass play and has allowed 19 sacks in the past three games.

'Not going anywhere'

Smith bristled when reminded that there are critics of a philosophy that he used to take the Bears to the Super Bowl during the 2006 season.

"I've been doing this defense since 1996, and whoever says that doesn't know what they're talking about," Smith said. "So I'm not even going to try to get into defending it.

"When people say that about the Tampa 2, it's more than the Tampa 2. You play Cover 2, but it's just a small part of what we do. Every team in the league plays some form of Cover 2. When it's described that way and how it can't work, Cover 2 has been around since the beginning of time and it's not going anywhere."

Frazier, meanwhile, believes the bye week helped Smith and him work through some of the issues of installing a new defense, particularly when it comes to giving up as many big plays as the Bucs have.

"You don't want balls going over the top of your defense," Frazier said. "So no matter what scheme we're running, that's still something on defense you have to get taken care of. I'm hoping — we all are — that through this bye week, we fixed some of those things that have given us problems."

Fourth-and-20 regrets

One of the many reasons Vikings General Manager Rick Spielman chose Zimmer to succeed Frazier was Zimmer's creativity when it came to designing and calling exotic defenses and making in-game adjustments.

No one can argue that the defense has improved markedly under Zimmer. However, the team is still 2-5 — only one game better than Frazier was a year ago — and is coming off a fall-from-ahead loss lowlighted by the Bills converting on fourth-and-20, third-and-18 and second-and-20 on the game-winning drive.

One of Zimmer's biggest regrets on the flight home from Buffalo was not calling a timeout with his defense on the field facing fourth-and-20 with 1 minute, 27 seconds left and the Bills 60 yards from the end zone.

On the surface, it sounds absurd for a coach to be even thinking of a timeout in that situation, let alone regretting not calling one. But look deeper and you will see a rookie head coach and his defensive coordinator, George Edwards, in the infant stages of trying to teach a new defense and orchestrate it under pressure.

Throw in a 25-second clock and Buffalo's decision to do a quick snap and, well, that fourth-and-20 was the perfect storm.

The sideline was slow calling the defense. When Buffalo snapped the ball, Greenway was looking over his shoulder to set the safety and the nickel corner. The tight end slipped past him, a pass was completed for 24 yards and, well, you know the rest.

Zimmer used Tampa 2

Greenway was asked to list some of the differences between the defensive schemes.

"Oh," he said. "There's a lot. We have a lot more volume in this defense. But we did have success with that other defense, too."

Greenway was then asked to explain the difference in personalities when it comes to Zimmer and Frazier.

"Obviously, they're different," Greenway said. "Complete opposites in their approach. But I think their passions are very similar. Just displayed differently."

Believe it or not, there was a time when Zimmer was a proponent of the Tampa 2 scheme.

"When I was in Dallas, we copied the Tampa 2," said Zimmer, who was Cowboys defensive coordinator from 2000 to 2006. "We copied it almost [completely]. I remember studying John Lynch and Warren Sapp and Ronde Barber and all the guys they had. Derrick Brooks. We ran it for a couple of years.

"It might have been my first year as defensive coordinator that we went almost exclusively to it. I remember and I talked to [then-Buccaneers defensive coordinator] Monte Kiffin. When I was in Dallas, I remember we were playing Tampa Bay. And John Lynch is telling, 'Hey, they're running our defense. They're doing the exact same thing.' "

That's not the case anymore, although Zimmer said the Vikings still use some of the same Cover 2 concepts.

Frazier, meanwhile, doesn't sound interested in trying to outduel Zimmer and his defense as he does in shutting down Norv Turner's offense and winning for the second time this season.

"When you're sitting at 1-5 as a team — and I'm not big into stats — but … that overrides everything," Frazier said when asked if the game meant more because the opponent is the team that fired him. "You look at where our division [NFC South] is and you realize that this win could get us started. So that really supersedes everything else. Our being able to get a win on Sunday would be so good for our team and what we're trying to get accomplished this season."