The A’s Signed the KBO’s Best Starting Pitcher

By | December 23, 2022
John Hefti-USA TODAY Sports

There have been a lot of transactions this past week. There’s been a lot of drama, too, involving a top free agent, a medical issue, and boatloads of cash. The long weekend is just around the corner. It’s been an exhausting year, and we’d all like to get on with our lives. Between relaxing on the sofa and reading up on Drew Rucinskideciding on which is the more appealing option doesn’t seem like a difficult task.

Which, fine, I understand. My livelihood isn’t affected by page views, so we’re cool here. But Rucinski isn’t just some random starter the Athletics chose as their annual innings-eater. When he last appeared in a major league game, he was a lackluster middle reliever for the Marlins. Since then, he’s undergone quite the transformation. Four years later, there’s an argument to be made that he was the best starting pitcher during his time in Korea. That’s a testament to how much he’s improved, in terms of stuff, command, and durability.

We can first consider Rucinski’s on-field contributions. Among KBO starters who’ve logged 500 or innings since his rookie season in 2019, here’s how he ranks in several categories:

Rucinski in the KBO, 2019-22

metrics Rucinski rank
IP 732.2 1st
ERA 3.06 3rd
FIP 3.50 3rd
K% 21.5% 1st
BB% 6.3% 4th
K-BB% 15.3% 1st

As the A’s might have appreciated, Rucinski threw the most innings of any KBO starter over his four-year stretch of excellence. He did so while routinely recording some of the best ERAs and FIPs in the league; Eric Jokish other Casey Kelly occupy the top two spots for both metrics, but they don’t have Rucinski beat by a large margin. Most of all, Rucinski, more often than any other KBO starter with a similar volume of work, found ways to strike hitters out. In a league where choking up on the bat is almost customary, eliciting whiffs is easier said than done.

Rucinski didn’t hone his technique overnight, though. In fact, if we just look at his rookie KBO season, he had one of the lowest strikeout rates among qualified starters. Something changed, but what? Not his zone rate, which remained essentially the same in each season. I did notice that the quality of his strikes improved, but it isn’t measurable using publicly available data on Korean baseball. He never really altered his pitch mix, though he did seem to endorse pitching up in the zone with his fastball last season. Instead, he solved whatever pitching problems he had with brute force:

Rucinski Velo by Year

Year Age FB Velo (mph)
2019 31 91.5
2020 32 91.0
2021 33 92.0
2022 34 92.6

Nothing to see here, folks. Just a 31-year-old pitcher upping his fastball velocity by a tick and a half by the time he’s 34. I mean, it’s not impossible, but it’s surprising because this doesn’t usually happen, and it allowed Rucinski to become one of the more dominant starters in the KBO.

What have helped is that in Korea, he finally found an opportunity to make regular starts, allowing him might to build his stamina over time. The initial lack of it also might have caused him to conserve his energy early on. A few seasons later, if he discovered the strength needed to throw at an increased effort throughout an entire season, that would explain why his velocity has trended up, not down. He doesn’t have much mileage on his throwing arm, and I don’t think he’ll age the way other starters typically do. A decline in velocity is inevitable, but it likely won’t be a concern for the A’s while they have him.

Interest in former major leagues in the KBO has spiked in recent years, and so have “re-exports” of these players back to the States. That means there are precedents we can consult. the good news It doesn’t seem like you need to be one of the very best KBO pitchers in order to thrive with a big league club. Take Merrill Kelly for example, who’s serving as the de facto ace for the rebuilding Diamondbacks. He, too, was pretty good in the KBO, but was nowhere near as great as Rucinski has been for the past few years. And yet he found success almost immediately upon his return to MLB and has continued to improve ever since. Or consider Chris Flexenwhom the Mariners decided to trust based on two thirds of a season. Their small gamble of two years and $4.75 million paid off instantly with his first year in Seattle, as he became the fifth starter the team needed. If Kelly and Flexen made it, so can Rucinski.

But for every Kelly or Flexen, there’s someone like Josh Lindblom, who signed with the Brewers after two great seasons with the Doosan Bears. At the time, he was around the same age as Rucinski is now, with a similar reputation for providing clean innings in bulk. And though he showed some promise in 2020, a series of disastrous relief outings coupled with injuries the following season made any chance of him sticking in the Brewers’ rotation kaput.

There’s a realistic chance that Rucinski flops. Bringing in a pitcher from a foreign league is a risky prospect, no matter how promising or trustworthy said pitcher might be. You’re hoping that he’ll adjust to a much higher level of competition in a relatively short period of time. Even if he does, the upside isn’t much; you don’t show interest in a KBO pitcher in hopes of adding an ace. The best case scenario is a no. 4, maybe a no. 3 starter.

That said, while I’m not sure Rucinski was the best KBO pitcher available, I’m almost certain he was the most accomplished. He had nowhere to go but up. The NC Dinos could have resigned Rucinski, but it probably would have cost them their entire foreign player budget, which is meant to sign up to three players. Besides, have you seen the going rate for a decent starting pitcher these days? The A’s guaranteeing Rucinski just $3 million*, in my humble opinion, is a bona fide steal. I’d legitimately consider taking him over Jordan Lyles or Kyle Gibsonboth of whom signed for much more.

Potential risk aside, Rucinski, by sharpening his command, adding velocity, and pitching deeper into games, blossomed into a viable big league starter. His next quest — applying what he’s learned overseas in a familiar yet new environment — will be his most ambitious to date.

*Note: There’s a $5 million club option for 2024. All KBO statistics courtesy of Statiz.

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