What can the Royals expect from Kris Bubic after his strong finish to 2021?

One of the more overlooked stories from the 2021 season was the solid last month of play from 24-year-old left-handed pitcher Kris Bubic. While Bubic often goes under-the-radar when compared to other young Royals pitchers in the system (especially fellow 2018 draft picks Brady Singer, Daniel Lynch, and Jackson Kowar), he has actually made his mark on the Royals in his first two seasons in the Major Leagues, despite not pitching above High-A ball prior to 2020.

In two seasons with the Royals, Bubic has appeared in 39 games and has made 30 starts, accumulating a 4.40 ERA in 180 IP. Granted, his career FIP (5.03), K/BB ratio (2.01), and fWAR (0.8) aren’t exactly impressive. However, there are signs that after the last month of play (and second half overall), Bubic may be on the upswing, which could be a good sign not just for his outlook at the Major League level, but the Royals rotation overall as well.

Therefore, let’s break down Bubic’s performance from 2021, and what needs to happen for Bubic to be a major factor in the Royals rotation not only in 2022 but beyond as well.


Utilizing the fastball more; Changeup less in the second half

One of Bubic’s most prized pitches is his changeup, which has always been rated as a plus pitch, even during his days as a prospect in the Royals’ farm system. Last season, of his three pitches (four-seamer; changeup; curve), Bubic’s offspeed offering generated the highest strikeout rate at 23.7 percent, according to Baseball Savant data.

Here’s an example of Bubic’s changeup getting Angels slugger Anthony Rendon to strike out swinging at Angels Stadium back in June:

However, while Bubic’s changeup may have been his best offering last year in terms of striking out batters, it wasn’t necessarily his most effective pitch overall.

His changeup actually produced a run value of +8, which was only one run better than his curveball, his worst pitch in 2021 on a run value end, according to Savant.

In addition to lackluster run value numbers, take a look at the other metrics associated with Bubic’s changeup from Savant’s run value data:

Notice how his changeup not only had the highest hard-hit rate of his three pitches, but also the highest expected slugging and expected wOBA as well. Thus, while Bubic’s changeup wasn’t his worst offering last year (that honor belonged to his curveball), the results could have been worse with his changeup last season, had batted ball luck or the Royals’ infield defense been different.

A big issue with the changeup last year was Bubic’s command of it, and that is obvious when Royals fans compare his changeup pitch heatmaps on base hits and outs via Savant.

Here’s a look at what his changeup heatmap looked like when hitters connected on his changeup for base hits last season:

Notice how the deep red area is primarily in that middle area of the strike zone, specifically slightly inside to left-handed hitters, and outside to right-handed hitters. That lackluster command, especially of a pitch that clocks in on average at 80-81 MPH, produced bombs like this one to left-handed A’s first baseman Matt Olson (notice how the changeup is located right in that red zone from the chart above):

In the month of June, Bubic threw his changeup 38.7 percent of the time, which was the highest usage of the pitch for any month last season. However, hitters hit six home runs and posted a .846 slugging percentage on the pitch during that month of play, thus showing that Bubic needed to make an adjustment with his pitch mix if he wanted to stay in Kansas City for the remainder of the season.

Bubic did make an adjustment thankfully, as he utilized his changeup less and four-seamer more for the remainder of the season, as evidenced in his monthly pitch usage chart from 2021, via Savant:

Now, Bubic doesn’t possess an “elite” fastball by any means, as he only averaged 90.9 MPH on the four-seamer a season ago. However, he found a lot of success with it in the second half, as his whiff rate increased to 22.1 and 22.3 percent in August and September (from 18.7 and 18.1 percent in June and July) and xBA decreased to .224 and .195 over that same time span (from .324 and .280 in June and July as well).

The former Stanford Cardinal also found a lot of success on the four-seamer on that arm side area of the strike zone when it came to striking batters out, as demonstrated in his K zone chart below:

In the clip below, notice how he paints that outside edge of the strike zone for a called strike three with a 94 MPH fastball to the Twins’ Josh Donaldson at Target Field in September:

An interesting development was that Bubic’s four-seam fastball velocity had its highest average MPH over the last two months of play, despite Bubic throwing it more in the last two months than earlier in the season.

Take a look at the fastball velocity increases by the month in the table below:

Thus, it will be interesting to see if Bubic can perhaps maintain that August-September four-seam velocity for the whole season in 2022. If he is able to, that could not only go a long way in terms of maintaining the value on his four-seamer (which was his best pitch on a run value end at -6), but it could also help make his secondary pitches more effective as well (changeup especially).


Limiting walks and home runs in 2022

A big issue for Bubic last year was his inability to limit walks and home runs on a consistent basis, which ended up hurting his overall line.

In 2021, Bubic posted a BB/9 of 4.08, which was 12 points higher than his BB/9 in 2020. That resulted in a lower K/BB ratio at 1.93, which was 30 points lower than his 2.23 ratio in his rookie season.

Granted, struggling with walks was an issue for many of the Royals’ young starters in 2021, as Bubic actually ranked second in K/BB ratio of the Royals’ five promising young pitchers, including Singer, Lynch, Kowar, and Carlos Hernandez. Notice how Bubic compares in K/9, BB/9, and K/BB ratio data of that group, and Bubic’s regression doesn’t seem so bad when compared to his fellow Royals pitchers.

However, while Bubic looks okay on a K/BB ratio in comparison to Hernandez, Lynch, and Kowar, being a sub-two K/BB ratio pitcher is not ideal in the long-term, especially for a pitcher without a high-velocity four-seamer or sinker fastball.

In addition, the BB/K ratio is also not good when combined with the fact that Bubic was the second-worst pitcher of that group when it came to giving up home runs last year, as evidenced by his 1.52 HR/9 (only Kowar was worse at 2.08).

Let’s take a look at Bubic’s BB, K, and HR per nine innings data by month last year, and see if we can find any trends or developments:

Notice how between the months of June and August, Bubic was really bad when it came to giving up home runs. Even though his K/BB ratio slightly improved to that 2.00 benchmark, his 2.38 HR/9 was his second-worst HR/9 mark in a month last season.

Furthermore, take a look at his heatmap on home runs allowed from August:

And for a further visual, let’s take a look at how the Cardinals’ Nolan Arenado crushes a sub-par 89 MPH fastball thrown in that “red” zone over the left-field wall at Kauffman Stadium on August 15th:

Therefore, Bubic will need to command and locate his pitches better over the course of the long season in 2022, to not only limit walks, but also long balls like the one from Arenado above.


Outlook on Bubic for 2022

Bubic looked like a starter who could be part of the Royals rotation for a long time during the last month of play. In 32.2 IP in September/October, Bubic posted a 2.20 ERA, 2.89 K/BB ratio, and 3.35 FIP, all stellar marks. Additionally, his second-half FIP of 4.36 was much better than the 6.15 FIP he posted in the first half, which thus shows that Bubic was improving after the All-Star break, even though the “substantial” progress didn’t come until September/October.

The big priority going forward for Bubic will be limiting those walks and home runs and finding a way to do so with his current pitch mix.

Bubic gained more confidence and velocity in his four-seamer during the past two months of play, and it will be interesting to see if that velocity can be maintained in Spring Training and the beginning of 2022, or if it was simply a product of the warm weather of those last two months. I am not sure how effective Bubic can be as a 90-91 MPH fastball pitcher long-term, especially if his walk rates don’t dramatically improve.

However, if he can average a four-seamer at 92-94 MPH, as he showed down the stretch? Well, it’s possible that Bubic could solidify himself as a No. 2 or No. 3 starter in the Royals rotation as soon as next season.

Bubic may not have the most upside of the young pitchers in the Royals organization. Furthermore, the presence of pitchers like Jon Heasley, Angel Zerpa, and Asa Lacy, who all could see some time on the mound in Kansas City in 2022, will only put more pressure on Bubic (and the other four young Royals pitchers) to produce early next season.

That being said, there were a lot of promising signs that Bubic is growing as a Major League pitcher.

Let’s hope those walk and home run rates can decrease next season…

Not just for Bubic’s sake, but the Royals as well.

Photo Credit: Nuccio DiNuzzo/Getty Images

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