DUNEDIN, Fla. — At this time last year Aaron Sanchez was fighting. Coming into spring training after a rigorous off-season featuring two-a-day workouts and a strict eating plan broken down by the hour, he had to battle for a spot in the Blue Jays’ rotation. Every time he entered a game was a test. There was no room to experiment. He had to prove himself.

This year, things are different. With his spot in the Blue Jays rotation solidified, Sanchez has been freed up to try new things on the mound, refine his game, and use Grapefruit League outings to test himself in a different way. That’s why much of his work this spring has been dedicated to the development of his change-up, a pitch he threw just nine per cent of the time last year but will likely feature more prominently in his 2017 arsenal.

“It could really do wonders for him,” says Blue Jays manager John Gibbons. “Hitters have to gear up for his fastball. They’ve got to swing early. So, a little off-speed pitch can really get them out in front, and probably even get a lot of swing-and-misses. A lot of groundballs, too. It’s a big weapon that he’s going to need for the rest of his career. And it’s showing good signs.”

Take Sanchez’s outing Thursday against the New York Yankees. After throwing nine straight fastballs to start the game, establishing the lively heater he leaned on nearly 75 per cent of the time last season, Sanchez and his catcher, Jarrod Saltalamacchia, started getting to the change-up.

With runners on first and second, and Chris Carter at the plate, Saltalamacchia called for the pitch for the first time on the afternoon. It wasn’t his best one. Sanchez spiked it and the ball got away from Saltalamacchia as both runners advanced into scoring position. Sanchez took a deep breath on the mound, looked in for the next sign, and saw Saltalamacchia flash the same fingers, wanting to go right back to the pitch again.

“He could see it. He knew that I didn’t like that first one,” Sanchez says. “And instead of waiting a few pitches, why don’t we go right back to it right away?”

Saltalamacchia showed great confidence in his pitcher doubling up on the pitch; and Sanchez showed great poise in making a small adjustment to the way he threw it. The 24-year-old executed it much better the second time around, getting Carter to ground weakly to shortstop, which would have been a double play groundball if he had thrown it that way the first time.

It was a small thing—just a two-pitch sequence in his outing. If you were looking at your phone you might’ve missed it. But the information gained from that live test was invaluable.

“I knew what I needed to do differently from the one that I spiked,” Sanchez says. “It was just making sure that I get that feel for it. Getting used to it. Throwing it in games, building confidence with it—that’s the biggest thing with that pitch.

“For me, it’s understanding the situation of when to use it. I’m confident with what I’ve got with that pitch. I just haven’t used it in enough game-like situations. There’s 100 per cent confidence with the pitch. It’s just understanding when to use it and how to use it.”

These are the adjustments Sanchez will have to make if he’s going to repeat the tremendous campaign he put up in 2016, when he led the American League in ERA and finished seventh in Cy Young voting. The book is out on him. He’ll establish his fastball early before using his curveball to try to get you out. Once a league’s seen you enough times and built up enough video on what you like to do, you have to make tweaks and changes to keep them guessing.

That change-up—which the Blue Jays would actually like Sanchez to throw a touch softer than the 89-90 mph it’s averaged since 2015 —gives hitters something else to worry about. It also opens up new sequences for Sanchez, who has been throwing more first-pitch curveballs and change-ups this spring as he works on starting fewer at-bats with his fastball.

“I tell you what, the guys that have really good change-ups—just look at Estrada, he can throw it any time,” Gibbons says. “They get an idea of what the hitters doing in the box, his timing, the situation. This is the perfect time to use it. You don’t want to break it out in the season and not have confidence in it and get burned by it. If it turns out the way he wants, it could be a big pitch in some really important situations once the season starts.”