JACKSONVILLE – There are many storylines – and in another sense, there really is only one.

That's the reality of Jaguars 2015 Organized Team Activities, which began Tuesday on a sunny, sweaty morning at the Florida Blue Health and Wellness Practice Fields. That's the reality, too, of the entire Jaguars' offseason, not to mention the training camp that will take place in a little more than two months.

The Jaguars have many key storylines. They're all intriguing …

And they all pale in comparison to the storyline of Blake Bortles.

That's not to place pressure on the second-year quarterback, nor is it to diminish tight end Julius Thomas, the young wide receivers, a young offensive line or a defense that will be key as all of those offensive pieces come together. We just mention it because it's true, and it's why Bortles' post-practice comments were the biggest story on Tuesday's Day One of 2015 OTAs, just as they will be the biggest story when training camp begins and just as …

Well, you get the idea.

Bortles, the Franchise Quarterback To Be – the Franchise Quarterback That Must Be, that the Jaguars Need Him to Be – is the story until he's not the story. And as OTAs begin, the story is Bortles' fundamentals – namely, the work he did on those fundamentals in the offseason and how they will translate to the field.

So, naturally, that was a topic Tuesday.

"To me, it's a big difference – to the guys that I worked with, it's a big difference," Bortles said. "It's just more efficient. It's better."

It was a topic for Jaguars Head Coach Gus Bradley, too.

"I've seen his footwork; his mechanics I think are better," Bradley said.

That's it … the Topic of the Jaguars offseason.

Bortles since being selected No. 3 overall in the 2014 NFL Draft has been remarkably candid about needing to improve his fundamentals. Because of that openness, those fundamentals are a primary focus until he proves himself a reliable, starting-level NFL quarterback.

And make no mistake:

Bortles has done more than talk about footwork. A whole lot more. He has worked to improve, spending two months this offseason with throwing-mechanics guru Tom House in Southern California. Bortles said it was "cool" Tuesday to put that work at last into team drills, adding that the process of turning all the offseason work into muscle memory – perhaps the most critical step – still was very much a process.

"One thing that was really cool working with those guys, was they kind of get you to do self-correction," he said. "They give you all these tools and say 'Here's how to fix it' … when it goes wrong, here's a checklist of things to go through and see where you were wrong at. So, I thought that was cool."

Bortles said Tuesday the mechanics are still something on which he must focus, but Bradley left little doubt he likes how Bortles has approached the task.

"He's not there yet but we've just seen really good improvement," Bradley said, adding, "I like what he did in the offseason. It's hard. The ideal thing is to be with us and to be with our coaches, but that can't happen (under NFL rules) so he took the next best thing and met with somebody, met with another player and threw in the offseason and really worked on it.

"I appreciate that and I think the team appreciates that. I think he did it for himself. We saw great improvement and now he's coming here and it's that muscle memory that he's dealing with, that every once in a while he goes back to an old style. He catches it now. He realizes he's done it and he gets back on course. That part we've got to keep working through, but I'm very pleased with where he is right now."

Those were encouraging things to hear for Jaguars fans. What was encouraging, too, were the words of Bortles' teammates.

Allen Hurns, a second-year wide receiver who worked with Bortles away from the facility during the offseason, said the tightness of Bortles' spiral and the velocity on his passes has improved significantly since last season. Marcedes Lewis, a 10-year veteran tight end, said the difference was evident on Tuesday.

"His mechanics, his footwork – his release is better just from his footwork," Lewis said. "You can definitely tell he went back home and sharpened up."

How critical is all of this?

As critical as critical can be. Thomas appears at this early stage to be a very good unrestricted free agent signing, and he looked good on Tuesday. The young wide receiver corps of Marqise Lee, Allen Robinson and Hurns can improve, and the expectation is it will. The same is true of the offensive line, and there's a feeling that a defense that turned into a solid unit last season can continue to improve even with the rookie first-round selection Dante Fowler Jr. out for the season.

But while those are key storylines, the development of a franchise quarterback is always The Storyline.

There's no doubt that's the expectation for Bortles. So far, there's a lot to like about his offseason. He has taken the right approach in the last few months, done the right things, and so far at least, it looks as if his progress is real.

If that keeps being real, there's no better – or more important – Jaguars storyline than that.