Braves Season in Review: Kirby Yates

Dec 2, 2022 - 3:00 PM

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Ahead of the 2022 season, there was the distinct possibility that some fans may have forgotten that the Atlanta Braves signed Kirby Yates. Yates, of course, was out of action due to undergoing his second Tommy John surgery in March 2021. His last appearance was August 14, 2020. When Yates finally returned to the mound after 724 days, he was part of one of the strongest bullpens in MLB (second in MLB in fWAR as a unit), but his continued rehab journey meant his effectiveness was limited.

How Acquired

The Atlanta Braves signed Kirby Yates to a two-year contract through 2023 with a club option for 2024 on November 29, 2021. This deal was low-risk, relatively high reward. It guaranteed Yates just $1 million in the first year, when it was known he wouldn’t pitch much, and $6 million in 2023, when he should be more fully recovered. In addition to the two-year guarantee, the Braves hold a club option for 2024 that would pay Yates $5.75 million if exercised, or $1.25 million via buyout if not.

With a fairly small guarantee, spread across three years, the main risk was just that Yates was eating up a bit of payroll with a fairly fraught injury history.

What were the expectations?

As recently as 2019, Yates led the league in saves. Since the start of 2017, his pitching triple-slash (ERA-/FIP-/xFIP-) was 64/62/64, which is approaching video game-y in nature. Yates’ 2019 was particularly insane: 3.4 fWAR as a reliever, which was second in MLB that year behind Liam Hendriks. Since that season, no reliever has put up over 3.0 in a single year, and that 3.0 belonged to 2022 Edwin Diaz, to put just how dominant Yates was in 2019 in perspective.

That said, Yates fell apart in a tiny sample in 2020 before hitting the shelf, and hadn’t pitched since, which has a way of limiting expectations. He wasn’t expected to do much in 2022, coming off said second Tommy John surgery. According to Fangraphs via RotoChamp, Yates was projected to pitch twenty-eight innings in somewhat above-average fashion.

It should be noted, expectations like this should always be taken with a grain of salt when there is such a small sample size involved. Given how little Yates was expected to pitch (and it turned out that 28 innings was quite generous), one earned run, or one walk, could drastically change his overall rate stats.

2022 Results

Kirby Yates ultimately struggled and probably didn’t meet even the sorts of “expectations” described above, although the term should be used lightly here. Yates only pitched in nine games, totaling seven innings of work. He had a 5.14 ERA, 7.26 FIP, 6.50 xFIP, 1.57 WHIP, and six strikeouts to five walks, all combining for -0.2 fWAR.

Yates not only had bad surface numbers, but he was a bit lucky as well. He was helped out with a high strand rate of 85.4 percent left on base (league average is typically around 70-72 according to Fangraphs), and a low BABIP-against of .200 (average is typically around .300 depending on the season). His FIP and xFIP were much worse than his ERA: 125 ERA-, 183 FIP-, 162 xFIP-.

On the bright side (if you want to call it that), his expected ERA (xERA) was lower than his actual ERA at 4.78.

Now, again, this was in only seven innings pitched after not pitching in an MLB game in 724 days. So, although these results were bad, it is nothing to be concerned with based just on these surface numbers themselves just yet. Not to mention, the way the contract was constructed, Yates was not meant to be the savior of the bullpen or anything like that in 2022.

Yates’ nine appearances came across the span of exactly a calendar month. He was activated on August 10 and got into a game that day; his last game came on September 10, and he was shut down with inflammation in his surgically-repaired elbow six days later.

What went right? What went wrong?

It is easy to pinpoint was goes wrong in a short cameo appearance where the results are bad, and it is no different with Kirby Yates. Yates’ issue in his limited appearances was his four-seam fastball. If a pitcher is going to be a two-pitch pitcher like Yates (albeit he maybe threw a single slider), the fastball needs to be at least somewhat effective. In 2022, this just simply was not the case.

Hitters had an xwOBA of .404 against Yates’ four-seamer. For reference, the league average xwOBA against the same pitch in 2022 was .341, which was the lowest it has been in the last five seasons. In other words, hitters were teeing off on it.

Since average exit velocity (EV) has been tracked by Statcast in 2015, hitters were hitting Yates’ four-seamer harder than they ever have. With an average EV of 93.3 MPH in 2022, it was that 2.7 MPH harder than his worst season back in 2015.

Hitters were also not missing the pitch. They had a whiff rate of 14.8 percent against it, which was far worse than the 41.1 percent we saw in 2020, when he had a few bad outings prior to injury (he did not pitch in 2021). In fact, the 14.8 percent in 2022 was the worst in his career.

Within the strike zone itself we can see that hitters were able make contact better against his four-seamer. Hitters’ whiff rate inside the strike zone was only 15.4 percent, while as recently as 2020 they were whiffing in the pitch at a rate of 39.1 percent.

This drop off in swing and miss rate inside the zone could be due to his four-seamer having the least amount of vertical movement of his career, and the second-least horizontal movement of his career (2016 was the lowest).

Combine these numbers with the fact that Yates threw his four-seamer 50.4 percent of the time, and he was destined to have bad numbers in only seven innings without a severe stroke of good fortune.

On a positive note, Yates’ surgery and subsequent recovery did not seem to effect his 4-seamer velocity very much. His four-seamer averaged 93.4 MPH; for his career, its average has floated between 93.0 and 93.9. A noticeable decrease in velocity can be an indicator that a pitcher has not fully recovered from, or adjusted, to the surgery. In Yates’ case, this does not seem to be the case.

Another bright spot for Yates is that his split-finger had positive results. Hitters had a terrible launch angle of 1 degree, which is right on par with what we have seen from Yates since he started using it in 2017. Now, hitters did have an xwOBA of .269 against it which is the highest of his career. The league average xwOBA against this pitch in 2022 was .230. So, his split finger was not elite by any means, but it was not awful. In fact, he was also able to generate a whiff percentage of 44.8 percent, which was his second-highest in a season since he started throwing the pitch.

Yates threw his split-finger 48.9 percent of the time. So, if he continues to use it at a high rate, while producing a high whiff rate and extremely low launch angle, we could potentially see him use this pitch as a legitimate weapon in 2023. But, he’ll need to actually be able to set it up with something that works a bit better than his four-seamer did.

Yates uses a pretty unorthodox pitching strategy to dominate earlier in his career, so it’s hard to say whether 2022 portends a problem in that regard. When he carved up the league in 2019, he combined an average-”rise” four-seamer that had a ton of fade and mostly threw it over the plate, low in the zone. He combined that with a splitter that also faded and really dropped low, attempting to clip the bottom edge of the zone. The differential between ultimate location between the two pitches was fairly small, but apparently substantial enough that Yates was near-unhittable. In 2022, his pitches lost some fade, but the big issue was that his fastball ended up belt-high instead of knee-high, and he seemed to try and force the fade by locating more armside, which completely ruined the pseudo-tunneling he used to benefit from.

All of this is probably splitting hairs: it was only seven innings, and Yates was coming off injury and hadn’t pitched major league innings in nearly two years. 2022 gives us a glimpse into how Yates might be effective in 2023, but it’s hard to build any kind of predictive analysis off of it.

Though Yates’ season overall was kind of a bummer, he did have a few bright spots. August 20 was one of the few times (and the last time) when he was used in something other than low leverage, and in that game, he threw a perfect inning against the eventual 2022 champs in a tie game. Here’s him getting the first out of that frame, with a splitter pounded into the ground:

That was a nice frame for Yates in an important situation. However, one a bit earlier went much more poorly: on August 12, Yates came into a game where the Braves held a two-run lead in the eighth, and promptly pooched it. He got an out, but then yielded back-to-back doubles to the murderer’s row of Jacob Stallings and Peyton Burdick. Here’s the run-scoring two-bagger that chased Yates and forced A.J. Minter to come in, strand the runner, and set up a tense one-run win thanks to some Kenley Jansen adventures in the ninth:

That’s not what a splitter is supposed to do...

2023 Outlook

Kirby Yates has recovered from Tommy John Surgery before, although at a much younger age. He also has an extensive history of being a well above-average reliever. With more time to heal up, and a full Spring Training to ramp up, Kirby Yates has the potential to be a key member of the Atlanta Braves bullpen in 2023. Bad results (really, bad everything) in seven innings after missing 724 days is not enough to throw in the towel on a pitcher who was a premiere reliever a few years ago.

Yates isn’t expected to be much beyond average at this point, but even that projection is a testament to just how good he was before going down with injury in 2020. It’s not a high bar to clear, but he’ll need to be further along in his recovery than he was in 2022 to do so.