The Oakland Raiders seemed to take only a passing interest in defense in 2012-13. Operating out of a 4-3 base defense, they allowed 27.7 points per game, ranking 27th out of 32 teams, according to NFL.com.
Such an underwhelming performance necessarily results from poor effort, but poor scheming can play a critical role. Thus, the coaching staff should re-evaluate its defensive approach from its basic components, so the players can be in the best position to succeed.
In line with what the Raiders should do to address its struggling offense this offseason, it's critical that they closely inspect the talent they have, the talent they should retain and the talent they reasonably can add over the coming months.
Considering all of these factors, here's why Oakland would be best suited transitioning to a 3-4 base defense.
The 3-4 defense uses three down linemen (two defensive ends and a nose tackle), along with four linebackers (two outside, two inside).
As you might expect, the roles of each position differ significantly from their counterparts in the 4-3, which uses four down linemen (two defensive ends and two defensive tackles) along with three linebackers (strong side, weak side and middle).
In the 3-4, the key defensive linemen is the nose tackle. An ideal nose tackle is large (up to 350 pounds) and capable of clogging the "A" gaps, or the spaces to his left and right between the center and the guards.
The defensive ends, meanwhile, typically are larger (between 280 and 300 pounds) than in the 4-3. In addition to pass-rushing, these players usually must be able to fill both the "B" gaps (between the guards and tackles) and the "C" gaps (outside the tackles).
The flexibility of the linebackers is what makes the 3-4 truly unique and dangerous. Conventionally, one outside linebacker is assigned a rush role, while the remaining guys offer run support or pass coverage.
However, defensive coordinators such as the Steelers' Dick LeBeau and the Packers' Dom Capers have become legends for mixing and matching roles using zone blitzes, which tend to rush five or six defenders and drop back the rest (including even nose tackles) into coverage.
The point is to confuse the offense into expecting a certain area of the field to be open, only to close it as the pass or the handoff is released.
Why use a 3-4 over the 4-3?
Some teams go with the strengths of the defensive coordinator, who may be versed in the system. Others might be compelled to make a change based on their existing personnel.
In the Raiders' case, both factors apply.
Second-year defensive coordinator Jason Tarver has a long background in the 3-4, going back to his days as the defensive coordinator at Stanford and with the 49ers.
Possessing a master's degree in biochemistry and molecular biology, Tarver entered the league with the reputation of being an immensely smart tactician who likes to employ a variety of defensive looks.
Last season, perhaps on the command of head coach Dennis Allen, Tarver stuck largely with a 4-3 arrangement. Although the team was able to blitz more than during its man-heavy heyday under late owner Al Davis, the results on the scoreboard were clearly not by design.
Given the Raiders' deficiencies last season, it only makes sense for Tarver to run a scheme he's comfortable with, provided he gets the go-ahead to try it.
Defensive end Andre Carter was a pleasant surprise for Oakland last season after suiting up from Week 6 onward. The former 49er and Patriot will be a key free agent for the team to retain.
Provided Carter returns, the Raiders will have three defensive ends who feasibly could start, including Lamarr Houston and Matt Shaughnessy.
The team could opt with Carter and Houston as 4-3 ends, with the oft-injured Shaughnessy coming off the bench. They would join two among the group of defensive tackles Tommy Kelly, Desmond Bryant and Christo Bilukiki (assuming the cap-strapped Raiders don't add a veteran in free agency).
But Kelly should be cut this offseason, based on his high 2013-14 salary and his propensity for penalties and other stupid plays. And Bryant and Bilukidi are too inexperienced and unproven to both be relied on to start.
As the team is deep in rushing ends and lacking in quality tackles, the smart move is to make Houston and Shaughnessy/Bryant the 3-4 ends, while shifting Carter to outside linebacker.
Houston, Shaughnessy and Bryant physically fit the mold of 3-4 ends. All stand between 6'3" and 6'5" and weigh between 285 and 300 pounds. All of them, particularly Houston, have shown knacks at times to get to the quarterback.
Carter, notably, has experience in the 3-4 during stints with Washington (2010) and New England (2011).
Although he is a natural defensive end, and the Patriots used him as such with good success, his size (6'5", 260 lbs) and rushing prowess would make him a better fit at linebacker if the Raiders make a schematic switch.
Middle linebacker was a troubling position for the Raiders last season.
Former top draft pick Rolando McClain submitted a mediocre-at-best campaign after a series of legal problems that bled into the season. The team suspended him for two games late in the schedule, though did not cut him.
He rewarded the team's faith by getting arrested again, albeit in humorous fashion, last month.
Given McClain's underwhelming on-field performance, there's little reason for Oakland to invite further headaches for another season. He should be cut as soon as the move would be prudent.
In his absence, the team would lack a dependable linebacker to anchor the middle in a 4-3 set. That opens the door for the Raiders to feature some difference-makers already on their roster.
Outside linebackers Phillip Wheeler and rookie Miles Burris arguably were the team's best defenders last season.
Wheeler had a team-high 109 tackles, demonstrating an ability to defend the run and perform ably in coverage. Burris used a physical style in amassing 96 tackles and an interception.
Based on their success outside in a 4-3, they are ideal candidates to act as the inside linebackers in a 3-4. Both have potential to rush in a zone blitz, as Wheeler had three sacks and Burris 1.5.
One of them also could shift to outside linebacker, depending on whom the team adds in free agency and the draft.
With converted safety Michael Huff as arguably the team's best returning cornerback, the Raiders clearly need to prioritize their secondary in the draft.
That said, a conversion to a 3-4 base defense would reveal some other clear-cut needs for the team to address from a deep talent pool.
A notable absence on Oakland's defensive line at the moment is a standout nose tackle. Even if he is retained, Kelly lacks the size (6'6", 300 lbs) and skills to clog the middle. The Raiders' best in-house option is Bilukidi (6'5", 320 lbs). But while the team is said to be high on him, according to ESPN, he remains an unknown commodity.
In addition, the team likely would need to add an outside linebacker, or an inside linebacker if Wheeler or Burris moves outside.
If the Raiders stand pat at No. 3 overall, they should have the option of selecting Utah defensive tackle Star Lotulelei (6'3", 320 lbs), who could plug in at nose and probably is the most complete defensive lineman in the draft.
The draft is deep in defensive linemen and linebackers, however. That would make a trade down for additional draft picks a much better choice for a talent-ravaged roster.
Later in the first round alone, Oakland could select Georgia linebackers Jarvis Jones or Alex Ogletree, Georgia defensive tackle Johnathan Jenkins, BYU defensive end/linebacker Ezekial Ansah or even controversial Notre Dame linebacker Manti Te'o.
The 3-4 would not be a perfect fit for the Oakland Raiders' existing roster.
But regardless of the defense they choose to run in 2013-14, they will have to manage glaring holes at cornerback, as well as the absence of at least one starter at defensive tackle and at linebacker.
Based on the background of defensive coordinator Jason Tarver, the abilities of the players who should return and the options the Raiders have to add through the draft and free agency, the 3-4 represents the best chance for the team to show meaningful improvement on defense as soon as next season.