That breakout has spurred something new for the Jaguars in 2016: expectations for success.
If Bortles is going to meet those expectations and liberate the Jaguars from their long stay in the AFC South cellar, he's going to have to show that last year was no fluke. That it was only the beginning.
It appears Bortles is all-in.
As Ryan O'Halloran of the Florida Times-Union reported, when the 2015 campaign came to a close, the Jacksonville coaching staff presented Bortles with some offseason homework. A to-do list, if you will.
The first order of business was a research paper and field trip, all in one. Offensive coordinator Greg Olson and quarterbacks coach Nathaniel Hackett wanted Bortles to pick the brains of two of the NFL's best at what they do.
That's how, as Bortles told O'Halloran, he found himself talking to Carson Palmer of the Arizona Cardinals and Aaron Rodgers of the Green Bay Packers about the finer aspects of playing quarterback at the game's highest level:
I bounced ideas off of them and asked them, "What would you do differently?" Aaron was awesome. One of the things he said was, "Don't try and score 21 points every time you have the ball." That's what I've had to learn.
Carson was good. He's laid back, and he's an unbelievable quarterback and leader in the NFL. He said similar things. He said, "Just continue to build chemistry and rapport with the guys you're with."
It's an interesting choice in mentors. Both veterans have had big-time success in the NFL. Rodgers is the athletic Super Bowl champion and MVP, while Palmer is the cannon arm whose career has widely fluctuated.
Their advice is sound, which shouldn't surprise anyone. It's sound for quarterbacks at every level, from Pop Warner to the NFL. Stay calm. Stay cool. Play within yourself and your offense, and let your teammates make plays. It's when signal-callers try to do too much that they run into trouble.
It's when Bortles tried to push things in 2015 when he committed one of his 23 turnovers—a number that has to come down for the Jags to be successful.
For all the things that Bortles did well in 2015, there were some dark clouds. Yes, he threw for over 4,400 yards. But he also failed to complete even 59 percent of his passes, a number that ranked him 32nd among qualifying quarterbacks at Pro Football Focus.
Then there are the sacks. Since taking over as the starter for the Jaguars, he has incurred 106 of them. He had 51 in 2015 (tops in the NFL) after a staggering 55 the year before. Yes, a porous Jacksonville line bears much of the responsibility for those sacks, but Bortles does too for holding the ball much longer than he should.
There are also the turnovers. Bortles' 17 interceptions as a rookie rate as something of an asterisk, as he's hardly the first young quarterback to be picked a lot in Year 1. But throwing even more in his sophomore campaign is a red flag.
There's one issue that can cause all those problems: trying to do too much with the ball. Pushing it downfield instead of taking what the defense gives you. Forcing the action while trying to make something out of nothing.
In other words, the antithesis of Rodgers and Palmer's advice.
Heeding that advice to stay cool is also going to come in handy when Bortles encounters bumps in the road. And make no mistake: there will be bumps in the road.
The biggest hazard to Bortles' development in 2016 may be his success in 2015. Many people only see the 4,428 yards and all those touchdowns. Stats no one expected. Stats they expect to get even better this year.
They are also stats no one should want if they're concerned with the Jaguars winning games. Yes, Bortles has a plethora of weaponry available to him in the passing game in young wideouts Allen Robinson and Allen Hurns and tight end Julius Thomas. But Bortles' statistical explosion last year said more about Jacksonville's inability to run the ball in the red zone than about Bortles as a player.
Garbage-time passing stats may make fantasy football fanatics feverish, but they aren't going to help the Jaguars get past Houston and Indy.
The good news is that from all appearances, the Jaguars get this. The team added Chris Ivory to help achieve more balance offensively. They signed tackle Kelvin Beachum in an effort to buy Bortles more time.
As Hackett told O'Halloran, they're working with Bortles every day in the hopes he'll make the most of it.
"Every day, we try to hone it down to a couple of things, whether it's footwork or understanding a situation or situationally," Hackett said. "Sometimes, I think we have to all sit back and go, 'Wow, he's still very young.'"
That's worth remembering too. Bortles, at 24, is a year younger than either Palmer or Rodgers when they made their first NFL start. Bortles' next will be his 30th.
These are heady days in Jacksonville. The Jaguars and the playoffs are being mentioned in the same breath—without laughter.
But it's important that player and team alike don't buy into the hype. That they maintain their composure, take one step at a time and go about the process of getting better as a team.
In other words, just do what Aaron Rodgers and Carson Palmer said.
As it turns out, they know what they're talking about.
Gary Davenport is an NFL analyst at Bleacher Report and a member of the Fantasy Sports Writers Association and Pro Football Writers of America. You can follow Gary on Twitter @IDPSharks.