The offense has thrived on a grind-it-out running game—or plowed ahead stubbornly, all the same, when the run hasn't been there. The defense has consistently ranked among the league's best, finishing in the top ten for yards allowed in three of Del Rio's first five years as coach until their surprising drop-off this past season.
Del Rio once described his team's ideal game as a "two chinstrap" affair—meaning you'd better pack a spare for when the first one gets popped loose.
Former linebacker Mike Peterson greeted the Steelers on Monday Night Football in 2004, "Welcome to Duval. Prepare to be hit," before a 9-0 slobber-knocker that showcased Jacksonville's gritty style on a national stage. Three different running backs hit 100 yards in a 375-yard rushing bonanza against Indianapolis in 2006, with one Colts beat writer quipping afterward that the Jaguars didn't hit 400 yards because "the end zone kept getting in the way."
All of which, in the aftermath of a 2008 season in which their ground game dropped 40 yards per game from its 2007 output and the defense got worse in every statistical category—not to mention the six-loss difference in their record—begs the question: What happened?
The answers are all up front, in the form of question marks that still linger on the Jaguars' offensive and defensive lines despite the team's best efforts to address them this past spring.
Despite investing heavily in their offensive line and welcoming back two key starters, the Jaguars are still counting on a rehabbed knee and contributions from two players who haven't played an NFL snap yet to resurrect their once-potent ground game.
Losing guards Vince Manuwai and Maurice Williams within the first fifteen minutes of the season sucked the life out of Jacksonville's once-killer rushing game last year. Williams is back from his torn biceps, but Manuwai is still rehabbing his injured knee.
Backup guard Uche Nwaneri was solid, if unspectacular, filling in for Manuwai at left guard as a rookie, and he offers solid depth for the Jaguars going forward. But Nwaneri doesn't have the lateral agility or balance to dominate in open space like Manuwai does.
For Jacksonville's power running game to work as well as it can, their interior linemen have to be able to pull and make second-level blocks—not just generate push at the line of scrimmage. If Manuwai isn't able to come back as the nimble road-grader he was before tearing his ACL, the Jaguars could struggle again to impose their will through the ground game.
Behind Nwaneri, center Brad Meester, and the motley crew of journeymen they brought in to play right guard—all straight-line blockers—backs Maurice Jones-Drew and Fred Taylor seemed stuck between the tackles. Coupled with unspectacular play from left tackle Khalif Barnes, who was allowed to leave as a free agent, and lumbering right tackle Tony Pashos, Manuwai's injury exposed a lack of athleticism in a group that had paved the way for the NFL's second-best rushing attack in 2007.
With a mind to fix that deficiency, new GM Gene Smith used his first two draft picks to bring in tackles Eugene Monroe and Eben Britton.
Both figure to challenge for starting spots immediately, and both would represent upgrades in terms of athleticism at any position along the Jaguars' line. Starting either, though, would come with the risks of leaning too heavily and too soon on inexperienced talent.
On the other side of the ball, Jacksonville will be expecting returns from last offseason.
Second-year defensive ends Derrick Harvey and Quentin Groves have an NFL season under their belts and will need to begin turning their potential into serious on-field production. The Jaguars' 29 sacks was unspectacular, if not necessarily atrocious, but their lack of consistent pressure allowed opposing passers to pick apart their suspect secondary.
Harvey led the team with 29 hurries and seemed more effective with his pass-rush moves later in the season, and Groves is committed to bulking up this summer in order to be an every-down end. And the Jaguars' ends will need to be able to anchor, by the looks of their situation inside at tackle.
John Henderson was once considered a three-gap terror in Jacksonville's aggressive one-gap defensive front. He'd attack the space between a guard and center, draw that double team, and still be a threat to make the play on either side of his blockers. This past season, he was handled one-on-one on occasion and seemed out of place in now-departed coordinator Gregg Williams' complicated, blitz-heavy schemes.
Coach Del Rio has touted new coordinator Mel Tucker as the overseer of a return to the simpler defense of the Jaguars' heyday, but Henderson could still use a bully partner like Marcus Stroud to draw opponents' attention off Jacksonville's pass rushers.
Gene Smith described Rookie Terrance Knighton of Temple, a beefed-up former receiver, as the draft's last potential starting defensive tackle. He joins grizzled veteran Rob Meier, undersized contributor Derek Landri, and a group of undrafted free agents competing to fill Stroud's vacancy a year after he was traded to the Bills for draft picks.
Jacksonville's "skill position" players on both sides of the ball are capable ball players. Behind a good line, David Garrard has shown he can manage a game—minimize turnovers, make timely throws, and hand the ball off cleanly to Jones-Drew. Free agent acquisition Torry Holt and the Jaguars' speedy crop of rookie receivers bring an element of short-area quickness to the passing game that's been lacking since Keenan McCardell left town.
On defense, Justin Durant is an up-and-coming talent at middle linebacker, and Rashean Mathis is an elite cover corner.
But the Jaguars will live and die this year, like they did this past season and every other year under Del Rio, by the performance of their offensive and defensive lines.
They've built both units the right way, drafting and developing their talent: Meester ('00), Williams ('01), Stroud ('01), Henderson ('02), and Manuwai ('03), were the brute force in the middle of Jacksonville's physical lines for half a decade. And they've tried to reload in the past two drafts to compensate for injuries and declines in performance.
Still, questions linger in the trenches, where the once-feared Jaguars will have to be tough enough to be competitive.