TORONTO — Jesse Chavez doesn’t love at-bats like these, but he doesn’t hate them either. He uses them to get better.

It was the eighth inning of Tuesday night’s series opener against the New York Yankees, and he had two runners on, two out, and Starlin Castro at the plate fouling off every single thing he threw. Chavez, the Blue Jays right-hander who is settling into a role as a high-leverage reliever, had been asked to get three outs so his team could try to overcome a one-run deficit in the bottom of the inning.

He’d already gotten two of them, on a ground out and a strike out, around a couple of singles that gave him a pair of base-runners to worry about as he tried to force Castro to make an out. He threw cutters down and in; fastballs up and away; curveballs at the bottom of the zone. Chavez threw just about everything that he could at Castro, who stood there in his batter’s box, patiently and persistently fouling it all off.

“The only thing I didn’t throw him was a change-up. Or I guess a knuckleball,” Chavez says the next day in the Blue Jays clubhouse. “It was a fun one. Just a back-and-forth chess match. That’s what baseball’s all about.”

Eventually, on the ninth pitch of the at-bat, Chavez threw a cutter away as hard as he could. He wanted to make Castro hit his best pitch; wanted to stay true to his approach and not give in to a stubborn hitter. He was tired; he was frustrated. But he was determined not to be the one that flinched.

The cutter felt normal coming out of his hand, but it practically detonated as it neared the plate, moving much more like a slider, tailing a foot and a half outside the zone at 92-mph as Castro flung his bat at it and missed. It was one of the hardest-earned third strikes Chavez has thrown in a while.

When Chavez arrived back at the Rogers Centre the next day for another game against the Yankees, he went back to his appearance the night before on video and watched the at-bat closely. He still couldn’t come up with words for what that final cutter did.

“Man, that one… that thing just… it just took off on me,” Chavez says, with a clear look of incredulity. “I wasn’t trying to do anything different. I was throwing it as hard as I can, but I do that every pitch. I was just committed to that cutter.

“[Castro] was on everything so I was just hoping he’d miss one or put it in play. It was a fun at-bat. I learned a lot from it. It’s always good to see what you can take away from something like that.”

Chavez was in the video room on Wednesday for exactly that reason, to analyze his entire outing and stay on top of his mechanics. The 32-year-old is one of the most cerebral pitchers in the Blue Jays clubhouse when it comes to the art of pitching and strictly studies everything he does with his hands, body and mind on the mound.

He starts with his legs, picking a point on the video screen and making sure his back knee stays in the same spot throughout each wind-up. He doesn’t want to see it waver as he delivers. Chavez knows if his legs are off, the rest of his mechanics probably are, too.

“Think of it like a building,” Chavez says. “Without a strong foundation, everything up top is going to sway, or even fall. So I make sure the legs are good and then I go from there. I just try to find some things I can take out to the field the next day and work on when we throw.”

Talk to Chavez for a while and you get the sense he’s constantly evolving as a pitcher. That happens to a guy who’s on his seventh stop as a pro ball player, and his second with the Blue Jays.

But this year is an especially challenging step in Chavez’s evolution as he transitions to a late-inning, high-leverage bullpen arm after spending his past three seasons as either a starter or a swingman.

Accustomed to working with clean innings and room for error, Chavez now finds himself in a role that’s seen him enter with runners already on base three of the four times he’s been called upon.

“You don’t have time to get a feel for a hitter or a lineup. You have to just come in and attack,” Chavez says. “I’m not used to having a guy on base when I come into a ballgame. It’s a different mind factor. You have to walk that line of throwing strikes while being fine at the same time, because you don’t want to give up one of those runs for the guy you came in for. That’s one of the worst things you can feel as a pitcher.”

Chavez speaks from experience. During the Blue Jays’ home opener last week against Boston, he came into the game with the bases loaded to relieve Marcus Stroman.

He earned a quick strike on Red Sox left fielder Brock Holt with a fastball down and away, and then tried to come back with a cutter in on Holt’s hands. It was meant to jam the hitter, but the cutter ended up down and in, right in the wheelhouse for a left-handed batter like Holt, who golfed the pitch 347 feet into the right field bullpen, one of the few spots in the yard where it could clear the fence.

“I felt miserable — just awful,” Chavez says. “Stro grinded all day to get to that point, and then it just gets out of hand with one pitch. Not even a bad pitch. A good pitch to the wrong guy. If it’s a righty, it’s a rollover. If it’s a taller lefty, it’s a swing-and-miss or maybe a take. But it just happened to be right where he likes it and where he’s comfortable with the ball. It sucked.”

For Chavez, that cutter to Holt and the one he struck out Castro with on Tuesday night perfectly illustrate the fine line he’s trying to walk as a high-leverage reliever. Throw commanding strikes, but throw them carefully, too.

“Just that little bit can be the difference,” Chavez says. “As pitchers, we tend to get lost in the justification process when things go bad. But you have to understand that sometimes you make the right pitch, just to the wrong hitter. It’s a learning thing. And now I’ve learned from that one to Holt. We’ve talked about it, I’ve gotten over it, and we’ll see how the next one goes.”

Chavez used the same routine after that unfortunate outing as he does with any other — hit the video room and take something away from it. He pored over the film carefully, searching for what happened to cause him to leave the pitch where he did. Instead of the result, he focused on the process.

“Little things like that go a long way, and I think they do matter,” Chavez says. “Watching it back is a big part of me getting over my own little habits on the mound. I instill that faith in myself that when I come in I know what pitch I want to use and I know how I want to execute it.”

That cutter is the pitch he’ll use most, and it’s been an extremely important weapon for him since he started to throw it in earnest three years ago. Chavez has leaned heavily on it this season, throwing cutters 44 per cent of the time, while mixing in the odd four-seam fastball and curveball.

The fastball is an important set-up pitch, especially as Chavez has significantly reduced his change-up and sinker usage out of the bullpen. He’s throwing the four-seamer nearly two miles-per-hour harder than he did last season, and using it to give hitters a slightly different velocity and look than his cutter, which is the pitch he really wants to throw. That’s because when he’s been able to locate this year, it’s been deadly, generating a swing-and-miss 30 per cent of the time.

“It’s all about location,” Chavez says. “You want to come in and have that conviction to put it where you want it with authority. Not overthrowing, but kind of blowing it out a little bit and still being able to hit your spots.”

It’s all part of it. Studying video, being a tireless self-analyzer, constantly considering what can be done differently and how he can improve — it’s all part of getting better. And sometimes, a nine-pitch at-bat with two runners on in an incredibly high-leverage situation can be the best way to learn.

“We had a conversation about this the other day, how in this division every game’s going to be a chess match,” Chavez says. “Regardless of how close the score is, it seems you’re always one swing away in this division. Every pitch is so important. I’ve had a couple at-bats that have really showed how true that is.”