Over the last couple of years, as Jameson Taillon got further away from his second Tommy John surgery, he’d had a thought in the back of his mind.

He wanted to figure out a way to improve his slider. It wasn’t as consistent as he would’ve liked it to be. He thought there was plenty of room for it to grow. And after being traded from the Pirates to the Yankees in January 2021, he joined an organization with a strong reputation for helping pitchers develop those “sweeper” sliders.

The problem was that Taillon just didn’t have the time to add the pitch to his arsenal. That offseason heading into the 2021 season was still affected by COVID protocols, and then the trade didn’t come until just a few weeks before pitchers and catchers reported to spring training. Last offseason, the lockout didn’t allow Taillon and the Yankees to communicate for 99 days.

So, the timing just worked out that this was the first winter where he really had the opportunity to work on his slider.

“I just feel like I have another gear that I can hit, and I feel like some low-hanging fruit was like, ‘Let’s make the slider better,’ whether it’s a new grip, or whether it’s just improving the slider I had,” Taillon said. “That was something I already had in my mind. A lot of the big home runs I gave up last year was on my slider. I had some good stretches with it, but I also had some bad stretches with it. So, I just want to eliminate that inconsistency factor, just add another weapon. It’s worth a shot.”

As much as Taillon wanted to add the pitch, it takes two to tango. After he signed with the Cubs in December on a four-year, $68 million pact, the two sides immediately discussed what they felt he should take the offseason to work on. Fortunately for him, the sweeping slider was very much something the Cubs thought he could add to his arsenal, too.

“We just kind of presented that with him as, like, ‘Look, things you already do well contribute to what we would consider a more sweeper-type breaking ball that you can generate more swing-and-miss and stuff in there as well,'” Cubs pitching coach Tommy Hottovy said. “So, just being able to use what he already does well and play with some grips and some thought processes about how to create that kind of sweeper-type breaking ball, we think it would help give him another weapon to get a swing and a miss or get some of that chase outside.”

It’s important to analyze the reasons why the Cubs thought of him as a candidate to add the sweeper in the first place.

That’s a process that began as soon as they identified him as a free-agent target. They researched what he does well, and they came to the conclusion that the way he throws his curveball actually lends itself well to the slider they want to incorporate.

Taillon’s curveball has two traits that also make a sweeping slider make sense. For one, Taillon’s curveball spin rate ranked in the 83rd percentile among major league pitchers in 2022 (per Baseball Savant). So, he clearly has the ability to spin the ball at a high level.

“You see what [Taillon’s] able to do with the curveball,” Cubs assistant pitching coach Daniel Moskos said. “That obviously gives you an indication of like, ‘OK, can you spin this the way you need to to be able to get the slider shape that we’re looking for.”

The second trait comes from the fact that Taillon can throw curveballs with more horizontal break than league average — though he can do so not because of his top-tier spin rate. He generates that movement due to natural seam-shifted wake (i.e., movement generated not from spin). In fact, despite Taillon’s ability to spin pitches well, he doesn’t do a great job at translating it to movement.

The Cubs think of Taillon as an ideal candidate for this sweeping slider because of his spin rate and seam-shifted wake. The idea seems to be to implement a slider that is actually designed for pitchers with heavy seam-shifted wake and high but untranslated spin rate.

“I would say the reason we settled on the slider that we did is it doesn’t rely on spin-induced movement as much,” Moskos said, “so you’re not trying to capitalize on useful spin. Before seam-induced movement became a thing, we used to look to, ‘OK, what’s the spin rate? How efficient is it? Where can we try and improve the shape of it, given those data points?’

“And so now, we’ve got a completely different data set and a completely different set of data points to be able to use to identify. It’s not so much anymore, like, ‘This guy doesn’t spin the ball well. There’s not much we can do with a break profile for his breaking ball.’ Now, we’ve got some workarounds for that.”

It sounds like the goal is to amplify Taillon’s natural ability to induce horizontal break without spin reliance. Currently, Taillon’s slider generates about 6 inches of horizontal break when thrown at 86 mph. The goal for his new slider is to generate 14-16 inches of break when thrown between 83-85 mph, Taillon recently told Marquee Sports Network’s Lance Brozdowski.

A slider with 14-16 inches of horizontal break is a big deal. We can predict the effectiveness of Taillon’s new slider based on his horizontal break goal.

Let’s say he does throw sliders with 14 inches of horizontal break at 83 mph. By using the parameters on which Cameron Grove’s Stuff Grade model is built, Taillon’s slider would rate as a 60/80 (one standard deviation better than average). His whiff rate (visualized below) would theoretically jump nearly three percentage points.

“That’s where the idea of the slider came from,” Moskos said. “Like, OK, he spins a curveball. That tends to perform a little bit better against lefties than righties. Can we create a more swing-and-miss type slider for him?”

In his first spring training start at Sloan Park on Monday, Taillon threw just one of those new sweeping sliders.

Taillon’s development of the pitch was one of the more notable pieces of news to come out of the early portion of camp. Despite that, the Cubs kept the plan simple for his first start of Cactus League play.

“We were kind of on purpose just not going to throw it too much today,” Taillon told reporters in Mesa, Arizona. “Just ease our way into spring training, and then as we get going, we can start really incorporating it.”

Being able to throw it more in game settings is just the next step in the process. Taillon said after his initial meeting with Hottovy and Moskos, he went out and threw the new slider with some positive results. He incorporated the sweeper into his bullpens after arriving to the Cubs’ spring complex, and he then took it into his first live BP a few days later. After his initial spring outing, he’s expected to add more sweepers to his pitch mix moving forward.

And each step of the way, one of the biggest keys to success has been to continue to develop confidence in the pitch.

“Confidence comes from multiple ways,” Hottovy said. “You can gain confidence in a bullpen setting if you’re consistently throwing it to where you want it to go, which he has shown. He’s going to be able to create movement and create the location that we want. Then, it’s just about going out there and doing it in a game setting. Every time you kind of crank that next level up, it’s going to challenge you to replicate it.”

With just under four weeks until Opening Day, Taillon has time to tinker with the pitch and see what works best. It’s obviously not a finished product yet, and there’s no guarantee that it ever will be.

Whatever the end result is, Taillon is set on taking this spring to try and add the sweeper into his arsenal.

“In a perfect world, it’s another weapon, swing-and-miss pitch to righties. I’m not afraid to try it,” Taillon said. “If it doesn’t work out and the hitters give me feedback that it’s not good or it’s not working — cool, I can always go back to the slider I threw. It’s a super simple grip, easy to remember. It’s been fun to experiment and try it out.”