JACKSONVILLE, Fla. -- The 2016 NFL season unofficially begins this week for the Jacksonville Jaguars with the start of the offseason conditioning program, and that means it’s make-or-break time for the team’s class of 2013.

Six players remain from GM Dave Caldwell’s first draft, and there’s a possibility that none of them could be on the roster when training camp concludes in August. At a time when the Jaguars should be working on signing some of those players to second contracts, they may instead be looking for replacements.

Both Caldwell and coach Gus Bradley said back in January that they would have no trouble moving on from players they had thought would be part of the core of their rebuild if they failed to meet expectations -- even those that were high picks.

"I think it’s about, as Gus always preaches, competition," Caldwell said. "If they get beat out or there’s a better alternative, we’re going to go with that route. How they got here doesn’t dictate whether they stay or whether they go.

"It’s whether or not they can help us get to where we need to go."

Receiver Ace Sanders (fourth round) and cornerback Jeremy Harris (seventh round) have already been released. Cutting a seventh-rounder is no big deal, but the Jaguars were hoping Sanders could become a big-play punt returner. He struggled on the field (averaging just 6.4 yards on 57 returns) and was suspended twice for violating the NFL’s substance-abuse policy before being waived.

How many of the remaining six could follow them out the door? Here’s a breakdown of each player from the class of 2013 still on the roster:

LT Luke Joeckel (first round): The Jaguars signed free-agent tackle Kelvin Beachum in March and Caldwell said the left tackle spot is wide open. Joeckel has been a starter since the day he was drafted. He started the first four games of his rookie season at right tackle before being moved to left tackle after the team traded Eugene Monroe. He suffered a season-ending fractured ankle in his first start at that spot. Joeckel started every game in 2014 and 14 games in 2015, missing two with an ankle injury. However, he has struggled, particularly against quicker rushers. Pro Football Focus tagged Joeckel with allowing eight sacks in 2014, but he did play better in 2015. The team says he allowed seven sacks, including five in the season finale against Houston. Beachum has started 39 games in four seasons with Pittsburgh, including 34 at left tackle over the past three seasons. Caldwell specifically mentioned Beachum’s athleticism and how well he works against speed rushers on the edge when asked what he likes about the former 2012 seventh-round draft pick.

S Johnathan Cyprien (second round): The signing of free safety Tashaun Gipson allows the Jaguars to use Cyprien as strictly a box safety. The Jaguars have tried to make the strong and free safeties interchangeable, meaning they could line up at either spot. That didn’t work well with Cyprien, who has played and started in 44 games in three seasons with the Jaguars, yet has only two interceptions, three forced fumbles, and 11 pass breakups. Cyprien is better when he’s closer to the line of scrimmage and essentially playing as a hybrid linebacker/safety. However, he’s going to have to beat out 2015 fourth-round pick James Sample to be the starter. Sample played strong safety at Louisville, but the Jaguars were working him at free safety last spring and he was about to get significant first-team reps at the spot when he suffered a broken arm during OTAs. He missed the start of camp but worked his way back and started at strong safety in Week 2 and free safety in Week 4 before a shoulder injury derailed his season.

CB Dwayne Gratz (third round): Secondary coach Dwayne Walker said Gratz was one of the team’s better corners during OTAs and minicamp, but he didn’t follow that up in the fall. He lost his starting job and was inactive for four games and lost playing time at nickelback to undrafted rookie Nick Marshall.

RB Denard Robinson (fifth round): Robinson led the Jaguars in rushing in 2014 (582 yards) but fumbled four times in the final three games of 2015 and the team signed Chris Ivory in free agency to be a complement to T.J. Yeldon. Robinson still offers the Jaguars a change-of-pace back, but the ball-security issues are a major problem.

S Josh Evans (sixth round): Evans has played in 47 games (36 starts) and has three fumble recoveries, five pass breakups, and no interceptions. He’s had some tackling issues but would seem to be on better footing after the Jaguars released Sergio Brown on Monday.

CB Demetrius McCray (seventh round): McCray started 12 games in 2014, three in 2015 and has six pass breakups and one fumble recovery. He also lost playing time to Marshall last season.