The 6-foot, 252-pound Carter, an All-America defensive tackle at the University of Miami and Denver's fifth-round draft choice in 1975, is thickly muscled, can bench-press 525 pounds and moves with exceptional quickness. His relative shortness enables him to get underneath the center at the snap and gain leverage against blocks. "If just a center can handle our nose tackle, we have no advantage with the 3-4," says Denver's Collier. "But if the nose man can force a double team, then we have a free linebacker to track down the ball. Rubin's strength is his ability to get away from blocks, meaning the opposition has to double-team at least."
Miami was the first NFL team to use the 3-4, employing what was called the "53" during its 17-0 Super Bowl season in 1973. This formation was the stepchild of something called the "over stack," a variation of the 4-3 in which three of the four defensive linemen were placed opposite the offense's strong side—the side with the tight end. The 53's genesis was a result of Defensive End Jim Riley's getting hurt. Rather than fill his spot, opposite the tight end, with an inexperienced down lineman, Defensive Coordinator Bill Arnsparger experimented with a standing linebacker instead. The Dolphins had borrowed the over stack from Hank Stram, then coaching at Kansas City. Stram had used this defense successfully while leading the Chiefs past Minnesota in Super Bowl IV. Poor Stram. He didn't know it at the time, but it wasn't the offense of the '70s he was on to, it was the defense of the '70s.
To fill the new linebacker position the Dolphins chose Bob Matheson, who had played some defensive end at Cleveland. The 53 was called the 53 because Matheson wore No. 53. In that first year the Dolphins thought of the 53 strictly as a pass defense. Matheson was inserted only in obvious passing situations and did most of the Dolphins' blitzing.
New England's Fairbanks has always believed in deploying the 3-4 against the run. At Oklahoma, Fairbanks had played a defense almost identical to the 3-4, but in 1973, his first year in the NFL, he switched to the pros' traditional 4-3. In two games Buffalo's O. J. Simpson gained 469 yards against the Patriots' 4-3, and Miami's Mercury Morris had 297 in his two outings against it. In all, the Patriots surrendered more than 200 yards rushing per game that season, finishing last in the league in that department.
Fairbanks spent the off-season studying game films and discovered that one of his 4-3 defenses, a version of Stram's over stack, had held up from tackle to tackle but had broken down badly on the outside. The problem: a lack of mobility on the flanks. The solution: substitute a speedy linebacker for a slow defensive end. Fairbanks promptly switched to the 3-4 as the Patriots' full-time defense. Around the league there were whispers that while Fairbanks had done all right with the 3-4 in college, this was the NFL and...well, you know.
In their first year with the 3-4 the Patriots jumped from last against the run to first. Rival coaches stopped whispering about Fairbanks and started to study his defense. One advantage of the 3-4 was obvious. Because it closely resembles the standard college defense, inexperienced rookies could move quickly and effectively into pro starting lineups.
But more important to NFL coaches are the flexibility and unpredictability of the 3-4—it is really several defenses rolled into one. Blitz a linebacker and—presto!—the 3-4 becomes the 4-3. What a team might lose by having one less lineman is compensated for by the fact that the offense doesn't know which linebacker will serve as the fourth rusher on a particular play. Blitz two linebackers and it is like playing the 4-3 and blitzing just one—though not for the offense trying to block it. "The 3-4 creates a great deal of offensive confusion," says Cincinnati Assistant Coach Chuck Studley. "Pro teams have had to devise whole new patterns of pass blocking."
Teams can use the 3-4 without making any adjustments in the standard zone pass coverage they employed in the days of the 4-3. That coverage calls for four short zones and three deep ones. In fact, if none of the 3-4 linebackers blitzes, then the defense has the flexibility of an extra man—a linebacker—in the pass coverage. That man can either create a fifth short zone—forcing longer, riskier passes—or he can be assigned to one particular player. In one game this season, the Broncos occasionally had a linebacker stick with St. Louis Halfback Terry Metcalf. As a result, Metcalf was never able to break free for the sort of long gainer that the Cardinals depend on, and St. Louis was shut out 7-0.
Miami has taken the 3-4's flexibility and unpredictability a step further by fielding a player who is both linebacker and lineman. He is Kim Bokamper, a 6'6", 245-pound former defensive end at San Jose State whom the Dolphins drafted in the first round in 1976. Bokamper never played linebacker in college, so he was understandably confused when a Miami assistant coach arrived on the West Coast to run him through linebacker drills several weeks before the draft. It wasn't until the Dolphins actually selected Bokamper that Shula revealed what he had in mind. Now when the Dolphins want to shift from the 3-4 to the 4-3, they don't have to tip their hand by sending an extra defensive lineman into the game. Just before the snap Bokamper, who usually plays left linebacker, simply moves up onto the line and gets down in a three-point stance.
What makes the 3-4 particularly successful against the run is the extra pursuit provided by the fourth linebacker. "Against the 3-4," says O. J. Simpson, "you have to settle for a three-or four-yard gain every time. It's much tougher to break a big one because the linebackers are in better pursuit position."