They include two defensive backs who showed plenty of promise as rookies. There is also room for a versatile, playmaking wide receiver.
He won't be the only pass-catcher who takes a step up, while two members of a developing defensive line will also begin to stand out.
Here are the six players the rebuilding Jags can count on as breakout stars in 2014.
All statistics courtesy of NFL.com.
Head coach Gus Bradley and general manager David Caldwell know how valuable Sen'Derrick Marks is to the Jacksonville defense. The pair moved quickly to award him with a four-year, $22 million contract, per Jason Katzowitz of CBS Sports, following a fine debut season in South Florida.
Marks was one of the few consistent playmakers along a pass-rush-shy defensive front. The cat-quick tackle generated consistent pressure from the interior. He finished the season with four sacks and a pair of forced fumbles.
Marks plays a vital role as the 3-technique in Bradley's hybrid version of the "under" front. He needs better play from the Jaguars' edge-rushers, as well as an injury-free run for nose tackle Roy Miller.
Then Marks will face more single blocking, helping him dominate in 2014.
Mike Brown emerged from relative obscurity to make a positive impression in 2013. The young wideout made 32 catches for 446 yards, including a pair of touchdown grabs.
Standing just 5'10", Brown still found ways to get open down the field. He proved himself a tough receiver armed with the field-stretching skills to win on the outside, evidenced by his 13.9 yards-per-catch average.
Brown has already shown enough of a knack for making plays to earn a greater role in 2014's offense. The Jags will need him to feature more often.
Fellow receiver Cecil Shorts III has talent but is still plagued by drops. The de facto go-to receiver, Justin Blackmon, is facing an indefinite suspension to deal with substance abuse problems.
What could help Brown is the rapport he established with streaky quarterback Chad Henne. He became a key target for the veteran signal-caller late in the season, catching 14 passes in the final four games.
The team is apparently determined to retain Henne, according to Vito Stellino of The Florida Times-Union.
Stellino isn't as sold on the quality of this draft's quarterback class as some and thinks the Jags could want Henne to start for another season. That would mean a lot more work for Brown.
But with either Henne or a rookie under center, Brown is sure to see a lot more passes come his way in the new season.
As the team's third-round draft choice in 2013, Dwayne Gratz naturally experienced some struggles, but the rookie rebounded to start seven out of the last eight games of the season.
He only missed the finale against AFC South rivals the Indianapolis Colts due to a sprained ankle. Despite the injury setback, Gratz had obviously earned the trust of Bradley and defensive coordinator Bob Babich.
The former Connecticut star fits the physical, press coverage schemes Bradley brought with him from the Seattle Seahawks.
At 5'11" and 201 pounds, Gratz has decent size on the outside. He also plays with a genuine nasty streak. He finished his debut pro campaign with two interceptions and three pass breakups.
Gratz can be even more productive in his second season in Bradley's schemes. This defense is strong at safety, so cornerbacks like Gratz can feel confident about being aggressive enough to take chances in single coverage.
Bradley and Caldwell need to bring free agent Will Blackmon back and may even add another corner, but Gratz will still be a key part of the rotation.
Expect him to get his hands on a few more passes in 2014.
Andre Branch is one of the strongest candidates to be a breakout player in 2014. He is currently the most dynamic pass-rusher on this defense.
He has good size for a rush end at 6'5" and 265 pounds, but he packs those pounds onto a lean frame and possesses the agility and quickness needed to torment offensive tackles.
The second-round pick in 2012 can be the hybrid "Leo" pass-rusher Bradley loves to feature on the edge. The youngster's chances of making that key role his own should be boosted by the potential exit of veteran Jason Babin.
NFL.com reporter Kevin Patra highlights the 33-year-old as a likely cap casualty:
The defensive end wants to stay in Jacksonville, but he's scheduled to make a base salary of $6 million -- currently projected as the eighth highest heading into 2014 -- which is overpaying for his 7.5 sacks. The team could restructure his contract to keep him in Jacksonville, but as it currently sits, he's a candidate to be clipped.
If the Jags add a player capable of occupying blocking schemes on the other side, and Marks continues to be active in the middle, Branch will be prolific in the new season.
Denard Robinson stole some headlines last offseason when the Jaguars briefly designated the wide receiver taken in the fifth round as "OW," for offensive weapon, on the depth chart.
But it was actually fourth-round choice Ace Sanders who became the roving weapon for the Jacksonville offense. Coordinator Jedd Fisch got creative by allowing the ex-Gamecocks playmaker to attack defenses in a variety of ways.
The most striking example came in Week 14 against the Houston Texans. Sanders took a screen pass and launched a 21-yard scoring throw to running back Jordan Todman. The trick play was one of the key moments in a 27-20 win.
More than just gadgetry, though, Sanders also proved himself a competent receiver. The pint-sized pass-catcher made 51 receptions for 484 yards.
Sanders has shown he can be that "joker" in the pack defenses often find so hard to counter. Fisch can continue to move the 5'7", 178-pound speedster around formations to free him in the open field.
After only scoring one touchdown as a rookie, Sanders will show up in several end zones in 2014.
It won't take long for Johnathan Cyprien to be acknowledged as a top-notch young safety by the rest of the NFL. The former Florida International standout enjoyed a fine first season as a pro.
Cyprien wasted no time becoming the heartbeat of the Jacksonville defensive backfield. The second-round pick a year ago simply makes plays.
Cyprien tallied 104 combined tackles, including 87 solo stops. He also broke up six passes, intercepted another, notched a sack and forced a pair of fumbles.
That level of production is ample evidence of real talent at his position.
Cyprien has shown the range to occupy the Kam Chancellor role in Bradley's mix of single-high and 3-deep coverage concepts.
That calls for a safety physical enough to lock up receivers underneath, while crafty enough to hover in zones and fool quarterbacks with late drops.
Cyprien already fits that mold as a feared hitter who combines ferocity with a natural instinct for reading offenses.
With Marks up front while middle linebacker Paul Posluszny patrols underneath, Cyprien is at the tip of a capable spine that can make the Jacksonville defense a force in 2014.
This active and punishing safety will be key to everything the unit does.