DUNEDIN, Fla. -- It's 9:53 on a cloudless spring training morning. For the rest of the Toronto Blue Jays' pitching staff, it's time for a break. Not for Aaron Sanchez.

For Sanchez, the reigning American League ERA champ, it's time for another visit to the Marco Estrada Changeup Academy.

After a winter spent reflecting on what he can do to take yet another step toward ace-hood, Sanchez's deliberations led him to a pitch he has never fully developed but one he thinks "would change me tremendously."

Obviously, Sanchez doesn't "need" to change anything. His fastball is already a force. He's mixing in more four-seamers. And his curveball is often a knee-paralyzer. But ...

His changeup was also a nearly unhittable pitch for him last year -- when he threw it. And when he commanded it. So the man who delivered it saw enough to decide it could be a devastating weapon.

"I think my changeup is a really good pitch for me," he said. "I know people tend to say it's too hard. I've watched video on it all of last year. And the swings and misses I got, the weak contact that I got, [tell me] it's a really good offering."

To improve on that offering, he turned to Estrada, the changeup guru himself -- a man in the running for Best Changeup on Earth.

How do their sessions work? Just listen to them talk about the pitch.

Aaron Sanchez (right) went 15-2 and led the American League in ERA last year. His plan for improvement? The Blue Jays righty enrolled in changeup school -- with teammate Marco Estrada. Jayson Stark/ESPN

Sanchez: "I'm trying to be the best I can be. And my biggest thing in spring training is the changeup."

Estrada: "The response to that is, he doesn't need it. ... No, he doesn't need it. He had a really good year last year, and I can probably count all the changeups he threw. You know, it wasn't very many. So I don't think he has to change anything."

Changeups in 2016: Estrada vs. Sanchez Estrada Sanchez Pitches 811* 267 Opp BA .159 .133 Opp SLG .301 .183 Strike pct 64% 53% Strikeouts 85** 10 * Second in MLB (David Price, 814) ** Led MLB

Sanchez: "I try to ask questions like: What do you feel when you throw that pitch? And what makes your changeup so great?"

Estrada: "I don't know, to be honest with you. I mean, I grab the pitch and I just throw it."

The two Blue Jays have bonded over a pitch Estrada has mastered -- and Sanchez is looking to bring to the next level. Rick Madonik/Toronto Star via Getty Images

Estrada: "I don't think mine does anything special to be honest with you. I think it has a normal four-seam action to it. But my goal is just to make it look like I'm throwing a fastball and, obviously, the speed differential. I'm trying to get at least 10 miles an hour off my fastball [velocity], is really the only goal I have. I don't really care about the action. I just want to keep it down and make sure I sell it right."

Sanchez: "Mine is a little different. I think I consider more depth on the action. And it doesn't matter, the speed, with me. Mine is a lot different than Marco's in terms of velocity and stuff. So I may not be able to generate 10 miles an hour off [the fastball], but if I can get five to seven, with good action, that's what I'm looking for."

Estrada, though, thinks Sanchez is so good, he doesn't even need to throw more changeups. Tom Szczerbowski/Getty Images

Sanchez: "It's such a 'feel' pitch that you've really got to keep your delivery the same as a heater. And that's where I kind of get in trouble, is speed differential, because I generate so much power through my delivery that my arm works different. And it's hard to generate that increase, or decrease, in velocity."

Estrada: "It is a 'feel' pitch. Even I have trouble with it at times. I have games where I'm out there, and I have no feel for it. Those are scary games for me, because without that pitch, it's pretty difficult for me to get outs. But having feel, I don't know how to explain that, either. Feeling comfortable, feeling comfortable throwing it in any count. It's basically trying to have the same grip and not thinking about it."

After missing a whole lot of bats with it last year, Sanchez is determined to throw his changeup more -- twice as much, he says -- with help from Estrada. Tom Szczerbowski/Getty Images

Sanchez: "I guess [I want to learn from Estrada] just kind of where his release point's at, what he's doing with his hand in terms of how he's letting it go. There's times when I have problems sometimes cutting it off, sometimes [throwing it] with my hand open. So when I'm asking questions on how to deliver the pitch to the plate, I'm just kind of thinking about where's his eyesight ... on where he's trying to throw it, or does he feel it come off his fingertips, or is there a certain way he does it on a different pitch?"

Change is good • Among the 62 qualified starters who threw at least 100 changeups, Aaron Sanchez held opposing hitters to the second-lowest average (.133), third-lowest slugging percentage (.183) and third-lowest OPS (.368) in the whole sport. He gave up just one extra-base hit on his change all season. One. • How good is Marco Estrada's changeup? According to ESPN Stats and Information, he had a 40 percent miss rate with that pitch last year, the seventh-best among all qualifying starters. Over his last six starts, including the postseason, opposing hitters went 6-for-62 against that change -- with just two walks.

Estrada: "I don't think he has to change anything. But he and I have talked about [it]. ... It's something to give the hitters something to think about. You want to put it in the back of their heads. And I think that's all you really want to do with it. Now if it becomes something special, then obviously use it. But he's very talented. He doesn't need another pitch. And his stuff is that good. So it's a compliment. It's a compliment to him, to how good he is. But if he can pick one up, he's just going to be that much better."

Sanchez: "I'm just trying to build off what I started last year. When you come to the field, it's just about being consistent, trying to get better every day. And what better to learn from than one of the best in the game with this certain pitch. So I'm glad to be in the position to have a teammate like Marco where I have the luxury of picking his brain on certain things."

Sanchez meets the standard of, "It ain't broke. Why would he try to fix it?"

At age 23, in his first full season as a starter in the big leagues last year, he proved he could be pretty darned awesome merely by pumping one killer two-seam fastball after another. He unleashed the second-highest rate of fastballs (74 percent) of any qualifying starter in baseball. How'd that work out? Excellent.

He was the AL's youngest ERA champ in 30 years. He posted the lowest opponent slugging, lowest opponent OPS and lowest home-run rate in the league. That's a sign his plummeting two-seamer is so hard to elevate, or even make decent contact with, that his pitching coach, Pete Walker, says: "When he needs to make a pitch, you could know that sinker's coming and still can't do anything with it."

But life as a big leaguer is about evolution. The sport adjusts to you. So what have you got in your back pocket that will allow you to adjust back -- or even adjust first? For Sanchez, it's a changeup.

He would like to throw twice as many of them this year, he says, "just to let them know that I have that pitch." Now is the time to develop it, to keep firing questions at his favorite changeup professor and to find a way to somehow improve on the astounding season he just had.

Sanchez has no more innings limits to think about. He has no more worries about being sent back to the bullpen. Instead of that talk, what he hears out there is, "This dude could win a Cy Young." But he has zero fear of those expectations.

Asked if he feels ready to step into the pitching elite, he says:

"I think I've always been in that elite. People may not have seen it. But mentally, I play this game to be great."

This spring, the burgeoning ace of the Toronto Blue Jays has chosen his path to greatness: He'll be riding the winds of change.