JACKSONVILLE – The real offseason stuff is getting closer and closer.

By "real offseason stuff" we mean on-field stuff, which stands in sharp contrast to the off-field stuff that has dominated Jaguars conversation in recent weeks.

Here's a thing to remember as that stuff approaches: for all of the exciting news around the Jaguars in recent weeks – a slew of free-agent signings, the ongoing weeks and weeks of draft talk, etc. –  the familiar matters a whole lot, too.

The familiar, in fact, may matter more.

That's because while the recently-signed free agents matter – and while they will be key to the team's hopes in 2016 – the returning players matter just as much. Actually, they matter more because improvement more often than not in the NFL comes from within.

That's especially true around the Jaguars, a team with an ascending young offense that still must improve and a team that will depend on returning players to key a pass rush and a defense that also must improve for the team to reach its goals.

So, as March turns into April and the beginning of the offseason program in mid-April approaches, here's a look at five key returning Jaguars players – and what those players need to do for the team to take a big step in 2016:

1) Blake Bortles must develop – still.Wait. What? How could No. 1 not be Dante Fowler Jr.? Or involve pass rush? Because as important as Fowler's return is to this team, Bortles remains the key to the franchise's immediate and long-term future. He improved last season more than anyone had a right to expect, setting franchise records with 35 touchdown passes and 4,428 yards passing, but 18 interceptions were too many and he made too many young quarterback mistakes. Those young quarterback mistakes? They were OK last year. They were expected because he was, after all … a young quarterback. Still, if the offense is going to improve its efficiency, Bortles must improve his decision-making in key situations. Bortles right now is a very good young quarterback with almost limitless potential. He has work to do to reach greatness.

2)Fowler must be what the team hopes.This may put pressure on Fowler, but the reality is this team needs the No. 3 overall selection in the 2015 NFL Draft to perform like the No. 3 overall selection in the 2015 NFL Draft. That doesn't mean double-digit sacks immediately. That's a tough ask for a player who missed his rookie season with a torn anterior cruciate ligament. But the Jaguars do need Fowler to be a disruptive presence from the edge. All indications are that Fowler's rehabilitation has gone well and that he will be 100 percent – or very close to it – by training camp. The Jaguars need that to be the case.

3) Sen'Derrick Marks must be healthy – and stay healthy.Marks' return may be equally important as that of Fowler. That's particularly true for the short-term. The defensive line was disruptive through most of the 2014 season when Marks was healthy, and Marks' penetration from his three-technique defensive-tackle position in the middle of the defense was a huge reason. While many focus on the absence last season of his 2014 team-leading 8.5 sacks, the team also missed his ability to disrupt interior runs. He is coming off not only a torn ACL that kept him out the first five games of 2015 but a torn triceps that cost him the last seven games. The Jaguars need more than four high-level games from Marks.

4) Julius Thomas must be what the team hopes.Don't take this entry to mean Thomas was a disappointment last season. He wasn't, and his ability to create mismatches in the middle of the field helped wide receivers Allen Hurns and Allen Robinson put up huge numbers. Thomas, a tight end who signed as an unrestricted free agent in the 2015 offseason, missed the first four games of the season with a thumb injury, and needed time to get in synch with Bortles after that. He caught 27 passes for 292 yards and four touchdowns in a five-game stretch in November and December. The Jaguars need Thomas' production to approach that late-season stretch.

5) Dan Skuta must be effective as a pass rusher.Yes, another pass rush entry. This one isn't quite as critical as the return of Marks and Fowler, but it matters. The Jaguars plan to use Skuta as a Leo pass rusher in some packages next season. That's something the team planned to do last season following a Week 8 bye, but a groin injury kept Skuta out three of four games and the team never used him in a major way as a pass rusher. When he did rush last season, his physicality and strength made him effective. He also had five sacks in his final season in San Francisco in 2014, so history shows he can be effective rushing the passer. The Jaguars need him to be so again next season.