Forget what you learned about the 32 NFL defenses last season … it's time to go back to school.

Nineteen teams named new defensive coordinators in the offseason. The Cowboys don't have a defensive coordinator, but head coach Wade Phillips will call the defensive signals full time this season after Brian Stewart was fired. The Eagles have secondary coach Sean McDermott filling in for defensive coordinator Jim Johnson, who is taking an indefinite leave of absence as he is treated for cancer.

Pendergast goes from the Super Bowl to a two-win team.

(Otto Greule Jr./Getty)

Some defenses will be completely revamped, while others will look much the same. In front offices around the league, the new names in charge are simply seen as part and parcel of working in a business where patience runs short.

"It just shows you how much stress there is to win," said one veteran personnel man. "Coaches aren't given enough time."

We polled a panel of NFL insiders for their thoughts on the league's new defensive bosses, with an eye on finding those who would have the biggest impact in their first season. All respondents participated on the condition of anonymity.

Jim Bates, Tampa Bay Buccaneers
The Buccaneers will continue to use a 4-3 front, but Bates will likely be more aggressive than predecessor Monte Kiffin, and he will certainly employ man-cover schemes.

Gus Bradley, Seattle Seahawks
Bradley, who has been praised for his energy and passion, has moved quickly up the ranks as an NFL assistant. He was a defensive quality-control coach for one year at Tampa Bay before spending two seasons as the club's linebackers coach. However, head coach Jim Mora will have the final say on defense.

Frank Bush, Houston Texans
His charge: get more out a defense laden with first-round picks. Bush wants his defensive linemen to get up the field and for the defense as a whole to create more turnovers.

Dom Capers, Green Bay Packers
Our panel was unanimous on this point: Because the Packers were dead set on employing the 3-4, Capers was the right man for the job. "Everywhere he's been a defensive coordinator, he's had success," said one personnel man. However, whether he has the right front-seven personnel to succeed immediately is up for debate. "That's definitely a team that is taking a little bit of a chance," said another panelist.

Chuck Cecil, Tennessee Titans
He does not figure to stray much from the blueprint that Jim Schwartz followed in Tennessee. Will benefit from being able to rely on an experienced coaching staff for counsel and has the respect of the players.

Larry Coyer, Indianapolis Colts
Coyer replaces Ron Meeks, who moved on to Carolina. "They may be a little more stout defending the run," said someone familiar with Coyer's defenses. "It will take a little more time getting the bigger guys there [up front]."

Gunther Cunningham, Detroit Lions
Cunningham will coordinate head coach Jim Schwartz's 4-3 scheme. A complete turnaround of the NFL's 32nd-ranked defense from a season ago is unlikely, but the Lions have revamped their personnel for the better, particularly at linebacker, where Julian Peterson(notes) (strong side) and Larry Foote(notes) (middle) join talented Ernie Sims(notes) (weak side), who was forced to do too much last season.

Bill Davis, Arizona Cardinals
"I think they're going full-time 3-4," said one panelist. "At times [last season], they overachieved, and at times, they underachieved. I think you will be able to tell [if the defense will succeed] early on."

Ken Flajole, St. Louis Rams
Formerly the Panthers' linebackers coach, Flajole will help Steve Spagnuolo carry out the defensive scheme that worked so well with the Giants.

John Marshall, Oakland Raiders
Like predecessor Rob Ryan, Marshall garners widespread respect. "They may be the surprise of that division, for what they have personnel-wise," said one observer.

Greg Mattison, Baltimore Ravens
Unlikely to make major changes to Rex Ryan's scheme and has the benefit of working with much of the same defense that finished second in fewest yards allowed last season.

Ron Meeks, Carolina Panthers
He's a proponent of the Cover-2 defense after working with Tony Dungy in Indianapolis. Needs his front four to get up the field and create pressure.

Mike Nolan, Denver Broncos
Nolan is long on coordinating experience, but no one surveyed by PFW is projecting rapid improvement by the Broncos, who finished 29th in defense last season and are transitioning to a 3-4 front. "He'll do a good job," said one respondent. "I'm not so sure how quickly that will correlate to the [games]."

Clancy Pendergast, Kansas City Chiefs
Pendergast, like others on this list, is charged with installing a 3-4 scheme after the squad struggled using a 4-3 scheme, and probably doesn't have quite the personnel he needs to make a successful transition just yet. "He will do some things that are a little unorthodox or [things] you may see as unsound," one panelist said. But he added, "If those guys get there [on the blitz], they will have some success."

Mike Pettine, New York Jets
Will play a key role in game-planning and scheming, but head coach Rex Ryan will make the defensive calls.

Rob Ryan, Cleveland Browns
Our panel believes Ryan could succeed right off the bat in Cleveland, citing how he fared in Oakland on a struggling team and his ability to get his players to play for him as the primary reasons. "Talent-wise, I believe they have enough talent up front to do some things," one evaluator said. "I think how they do depends on how well they learn the system."

Sheridan, right, giving instruction during an offseason session.

(Jeff Zelevansky/Getty)

Bill Sheridan, New York Giants
Gets his chance to run his own defense after predecessor Steve Spagnuolo took the Rams' head-coaching job. He is expected to use Spagnuolo's framework while adding some of his own wrinkles, and he will be working with top talent.

Mel Tucker, Jacksonville Jaguars
One evaluator thought the young, personable Tucker, who was the Browns' defensive coordinator last season, would be a success with the Jaguars "because he's a fundamentals-type guy, and those guys will play for him."

Gregg Williams, New Orleans Saints
"[The defense] will be noticeably better," said an NFC evaluator. "I'm not saying it's going to be a top-10 defense. But he will help them."

SPECIAL CASES

Philadelphia Eagles secondary coach Sean McDermott
A rising star in the profession, McDermott has been groomed to eventually replace Jim Johnson.

Dallas Cowboys head coach Wade Phillips
As one personnel man noted, "he is about as good as you get" as a defensive signal caller.

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