Split decision: How a random Hawaii meetup linked Carmen Mlodzinski and Kirby Yates

MILWAUKEE -- Carmen Mlodzinski was desperate.

This was December 2023, following his first season in the Major Leagues. Mlodzinski had decided to spend the winter in Hawaii and needed a throwing partner. So the Pirates pitcher Googled professional baseball players in the area.

With a curious mind and a desire to expand his pitch mix, Mlodzinski became intrigued by Kirby Yates, a Kauai native whose career was transformed after adopting a splitter in April 2017.

Mlodzinski got Yates’ phone number through his agency and cold-called the two-time All-Star, not knowing what to expect.

“There were definitely some nerves there,” Mlodzinski said. “For me, that comes from respect. He’s had such a great career. He’s definitely somebody I’ve looked up to. If I can have the career he had, I’ll be pretty happy.”

The phone call couldn’t have gone better, and what followed had both independently describing this week as “a full-circle moment” when the Pirates traded for Yates at the MLB Trade Deadline.

Mlodzinski and Yates threw together that offseason in Hawaii, at Kauai High School where Yates’ older brother Spencer coaches.

Mlodzinski peppered Yates with questions about his splitter -- his grip, the intent and arm action necessary to make it dance -- and the latter was an open book.

It’s how Yates has always operated, a good veteran giving back. But he seemingly has a soft spot for someone wanting to nerd out over learning the splitter, which pretty much saved his career.

Yates struggled mightily with the Yankees in 2015 and was traded twice in six weeks following the season. Questions over whether he could stay in MLB persisted. But amid those struggles, he started asking Masahiro Tanaka about his splitter and two years later finally put what he learned into practice.

In Yates’ mind, it’s only right he does the same when approached by a younger player looking to better himself.

“I’m always open to sharing whatever knowledge I’ve got, however I can help people,” Yates said. “If there are young guys and they have questions to ask, I will always answer them as truthfully as I can and try to help as much as I can.”

It was certainly appreciated with Mlodzinski, who initially grew curious of the splitter via David Bednar, then grew comfortable enough to throw it in a big league game in 2025.

The pitch was good for Mlodzinski then, but in 2026, it’s become his best offering. Opponents are hitting just .175 against Mlodzinski’s splitter, with a paltry .223 slugging percentage. It has a whiff rate of 31.0%, while he throws it 26.5% of the time.

Successful splitters will matter a great deal, as Mlodzinski slides back into the starting rotation for Mitch Keller on Friday against the Mets at PNC Park.

“You look at the last five years, [splitters] have performed really well,” Mlodzinski said. “What makes the pitch so good is the inconsistency of it. It has such a late break. You have a changeup and a knuckleball, but the splitter is probably somewhere in between.

“You’re killing so much spin that it has a little bit of a wobble to it. It’s hard for a hitter to time up. Everyone’s splitter can be a little bit different, as well. That can play into your favor.”

That’s some of what Yates learned -- and what he told Mlodzinski when they met and threw together about a half-dozen times over a span of two or three weeks.

There are different pressure points that can make the pitch fade or drop. The trick becomes command, which Mlodzinski believes Yates does better than anyone with his splitter.

It sounds easy, but you’re doing this with a baseball wedged between your index and middle finger, mimicking fastball arm action and pronatating at the end.

When Yates was learning, former Pirate Chasen Shreve taught him about varying his arm speed to make the pitch do different things. In the offseason before debuting his splitter, Yates threw all the time with Alex Cobb, who would offer instant feedback.

Similar to the desperation Mlodzinski felt when needing a throwing partner, Yates knew he needed to master the splitter to stay in the big leagues.

“The thing with the split, once you find your way with it, I think everybody has their unique way with throwing it and what they do,” Yates said. “It’s a unique pitch. I don’t necessarily think two people throw it alike.”

Its usage across baseball has increased, too, in Yates’ mind because more data has become available to prove its value and previous concerns that it could be unhealthy have been alleviated.

In 2018, only 1.3% of pitches thrown were splitters. That number has increased to 3.5% and 3.4% the last two years. It’s still small compared to changeups, which sit around 10-11%, but that’s likely due to the difficulty of truly mastering a splitter.

Few, if any, have done that better than Yates over the years.

When Yates saved 41 games for the Padres in 2019, his splitter had a run value of 14, per Baseball Savant. Opponents hit .267 off the pitch last year, which represented the first time that number has been over .200 in a full season. Yates’ splitter has a .216 batting average against in 2026.

“Specifically with Kirby, I think it comes from his command,” Mlodzinski said. “He has such good feel of his four-seam fastball, such good feel of his splitter that he’s really only needed those two pitches to have a special career.

“I don’t have that command. But that pitch has gone a long way for me. I’m definitely glad he showed me it. Still a work in progress, as everything I throw is. But it’s been good for me.”

It all started with that random trip, where Yates was incredibly welcoming. In fact, while Kirby was busy with family obligations during a trip back home, Mlodzinski ended up going on a beachfront camping trip with Yates’ older brothers.

These days, the shoe’s on the other foot. Yates appreciated Mlodzinski reaching out so quickly to welcome him to the Pirates. Mlodzinski loves having Yates in Pittsburgh, knowing how much knowledge he can share.

“The reputation that comes with him is more than just him being a good player,” Mlodzinski said. “He’s such a good human. I think you see that already in the clubhouse. He’s very bright. People want to be around him. He’s a really good dude.

“I’m super excited to play with him and get to watch him. It’s gonna be awesome to see that splitter in person. Little bit of a full-circle moment, for sure.”

Jason Mackey: Jason.Mackey@pirates.com and @JMackey_PGH.