In football terms, at least in the minds of the teams’ higher-ups, genius is 1% inspiration and 99% salvation. All signs point to the Jets firing defensive coordinator Bob Sutton and changing direction again with a unit that allowed roughly the same number of yards this season as it did in 2006, but also allowed 60 more points, got worse against the run, and forced a league-low six fumbles in 2007.

In this league, there’s always a scapegoat. Sutton will take the fall. Bring in the next patsy.

It could be, as rumored, Rob Ryan, who, according to an NFL Network report, has been fired from a similar position with the Oakland Raiders. Last season, the Raiders had a surprisingly proficient defense, ranking third in total yards allowed, first in pass defense, and fifth in red-zone defense. This year, the Raiders fell back to earth, ranked 22nd in total yards, next to last against the run, and 26th in points allowed with 398.

One team’s has-been, evidently, is another’s genius.

Ryan, who is the son of former NFL head coach Buddy Ryan, and Eric Mangini cut their teeth under Bill Belichick in New England, and both became proponents of the 3–4 defense the Patriots have helped repopularize. But when Ryan went to Oakland, he played under Al Davis’s rules. The Raiders’ owner has preferred 4–3 defenses with brutish defensive linemen, do-it-all linebackers, and fast cornerbacks.

Ryan tried to implement the 3–4 with ill-fitting personnel — sound familiar, Jets fans? — but was only able to run it occasionally in Oakland before going to a four-man base. Rob might not carry the renown of his brother, Rex Ryan, the former Baltimore Ravens defensive coordinator, but he has earned a reputation as a players’ coach with an eye for talent.

If he does go to the Jets, that skill will be highly desired. The Jets’ middling defensive rankings — 18th in yards, 19th in points — underscore the fact that wholesale changes appear likely. There are decisions to be made with linebacker Jonathan Vilma, defensive tackle Dewayne Robertson, and safety Kerry Rhodes. The first two don’t fit the 3–4 but have some trade value; Rhodes, who will enter the final year of his rookie contract, is due for a big payday. He’s worth the money, but the Jets must decide if they will give him an extension with other needs pressing.

Clearly, the team hit big with its two top draft picks last year, Darrelle Revis and David Harris, and will build around them. Revis finished strong and Harris might have won Defensive Rookie of the Year had San Francisco’s Patrick Willis not led the NFL in tackles.

But it must be asked again: Should the Jets run a 3–4 defense? Clearly, it’s what Mangini and Ryan know best. And it has been proven that it can work — provided the personnel is there.

“It’s a personnel-based decision [to run a 3–4], period,” said one long-time NFL talent evaluator. “You can’t shoe-horn it in. Baltimore changed [to a 4–3] when they didn’t have the right guys. Oakland and Atlanta finally got smart after they tried to make [the 3–4] work. They didn’t have the guys. You need certain people to run it.”

Such as a nose tackle. Three-man fronts wear down the guys up front considerably, especially the nose, who faces multiple blockers on nearly every play. The Chargers have Jamal Williams. The Steelers have Casey Hampton. The Patriots have Vince Wilfork. And the Cowboys’ success owes a lot to underrated nose tackle Jay Ratliff, who filled in for an injured Jason Ferguson admirably.

The Jets have stuck with Robertson, a square peg in a round hole, because he’s the best they have there. Sione Pouha has flashed at times but isn’t a 50-snap defender. The best free-agent defensive tackle by a mile is the Tennessee Titans’ Albert Haynesworth, and the Jets have the cap room — more than $28 million with more contracts to address — to make a move, though he always has been a three-technique in four-man lines.

In addition to needing a good nose and two good ends (who are built more like 4–3 tackles), the team badly needs playmakers outside. After setting the world on fire after the bye in 2006, Bryan Thomas (2 1/2 sacks) was nearly invisible this season. Victor Hobson, a free agent, likely will move on. Harris is the kind of inside linebacker who could be a star in this system, but there’s no reason to think that his skills couldn’t translate to a 4–3 defense.

A closer look shows that few teams exclusively run a 3–4 these days. The Patriots have shifted back and forth, going to four-man alignments when teams ran on them. Many teams, including the Cowboys, run four-man lines in their nickel packages. The Jets have one of the worst run defenses but didn’t have the defensive linemen to run a base 4–3.

So if Mangini really wants to make a move to help his team, he should use what Ryan learned in Oakland and what Belichick has figured out in New England: You have to run multiple fronts. If you’re going to call yourself a 3–4 defense, at least add the flexibility of being able to slide into a 4–3. Perhaps the best free agent who can help in that regard is the Ravens’ Terrell Suggs, who’s as dangerous with his hand on the ground as he is standing up.

Change is coming — this much we know. With Darren McFadden likely out of reach with the sixth pick in the draft, a versatile defender such as Virginia’s Chris Long could be the pick. A lot of the cap space also will go toward fixing the depth, especially with many free agents expected to walk.

Ryan has the reputation as a fiery guy who could charge up a group immediately. His style of choice, man coverage outside and some blitzing, is aggressive enough that it could challenge veterans and weed out some of the flotsam that has permeated the roster.

The Jets need a spark. In the best defensive effort of 2007, in the 20–10 loss to the Patriots, the team used some one- and two-man lines. It appeared to fire up the players when they were handed a gameplan that varied dramatically from the vanilla schemes the Jets ran up through the bye week.

If the Jets make big changes, including hiring Ryan, they likely will improve defensively. Never mind that Sutton’s schemes weren’t the problem — Ryan will get a lot of the credit. At least give the recycling-friendly NFL people this: Former geniuses sometimes do a get chance to regain their reputations in new places.

Mr. Edholm, a senior editor at Pro Football Weekly, can be reached at eedholm@pfwmedia.