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Mason Miller of the Oakland A’s has taken Major League Baseball by storm this season, coming out of the bullpen with an electric fastball that tops out at 103.7 mph and striking out 56.7% of batters so far. He also has yet to allow a hit in his first 285 pitches this season, a remarkable feat considering the fact that the average MLB pitcher allows 7 per 100 pitches thrown. He has saved 8 games for the A’s, nearly half of the A’s current total of 19 wins, and is rumored to be on the trade block at the July deadline. However, Miller’s dominance comes as such a surprise because he wasn’t nearly as successful in his rookie season with the A’s last year, and because Miller has been able to thrive in an A’s organization known for its worst. facilities, the worst farming system and the cheapest owner who continually refuses to spend any money to improve the latter. Miller’s story is that of an underdog who overcame his surroundings to become successful in a place where few players can. I know everyone, including me, loves a good underdog story, so I’m going to break down how Mason Miller has evolved into the monster he is now through changes in pitch design, his arsenal and usage profile, and other factors. , which have contributed to his meteoric and unprecedented rise to the top of the relief pitcher totem pole.
Let’s start with the pitch design and compare how Miller throws the baseball in the 2024 and 2023 seasons. In 2023, Miller threw a four-seam fastball, a slider and a cutter, along with a changeup that he threw almost exclusively to lefties. However, he’s only thrown a four-seam and a slider this season (he’s also thrown 2 changeups, both to lefties, but that’s not enough to pull off a sample size), so we’ll only compare the four-seam and the slider because he threw them in MLB in his two seasons of . It’s obviously a huge deal that Miller stopped throwing his Cutter and Changeup, but we’ll save that for a bit later. Also, a quick note to any readers who are not fluent in Baseball Savant terminology, I will be comparing the vertical and horizontal movement of Mason Miller’s pitches to the MLB average. Here’s how Baseball Savant does it, in order of average drop (vertical motion vs. gravity) or break (horizontal motion) for all pitches over 2 mph and 0.5 feet long from the pitch you’re watching : remove any bias towards slower pitches or pitches that are missed further from the plate, which therefore have more time to travel further. Beginning in the 2023 season, Miller’s Four-Seam averaged 11 inches of drop that year, which was 1.2 inches above average, which makes sense considering he released it with a 1-2 o’clock slant. His Four-Seam was surprisingly lacking in arm lateral run at just 7.7 inches compared to the average of 7.6 inches, and because of that, the shape itself doesn’t faze me. However, as always with fastballs, velocity is king, and since Miller’s Four-Seam averaged 98.4 mph, it was still a very good pitch for him at 0.8 run value per 100 throws, which better than the league average. Miller’s Slider had 39.2 inches of drop in 2023, 3.6 more than league average, and had 8.4 inches of break, 3.8 inches more than average. Miller unleashed his Slider on the 8-9 o’clock bend, creating a Slurve shape with a similar amount of vertical and horizontal movement. Like Miller’s four-seam, the shape of his Slider isn’t all that unique. However, unlike his Four Seam, Miller’s Slider has significant breaks, making it an effective pitch on the inner and outer thirds of the plate. This is reflected in the run cost of the pitch, which is 1.4 per 100 pitches and is also above the league average.
To compare now to Miller’s 2024 season so far, his Four-Seam has lost 1.1 inches of drop and gained 1.4 inches of break. This is unique because normally we see an increase in flight (meaning a decrease in drop) or a break, but not both at the same time, as adjustments to the ball’s slope at launch change the direction of the ball’s spin from being more vertical. more horizontally or vice versa. The change we see in Miller’s Four-Seam is not due to a pitch adjustment, but rather to an increase in field rotation efficiency, which generally results in more movement because the gyro angle is reduced at release. Miller also greatly increased his Four Seam velocity, averaging from 98.3 to 100.9 mph, which leads us to believe that Miller may have also increased the pitch’s spin rate, another reason that the overall movement of the pitch may have increased. . as well as These changes have accumulated to increase the pitch value tremendously, from 0.8 per 100 pitches in 2023 to the current value of 2.0 in 2024. Miller’s Slider lost half an inch of drop and break from 2023 to 2024. However, the pitch accelerated to almost 2 mph in that range, just like his Four-Seam. This shape change is fairly minor, but the drop of just under half an inch in pitch made it extremely understated in its speed range, going from 3.6 to 5.2 inches more drop than average height at 2 mph below its speed. This caused a huge increase in the run value of the pitch from 1.4 to 4.1. It’s clear that both Miller’s Four-Seam and Slider have seen significant improvements in the offseason, both in speed and form. So now let’s dive into how and when Miller uses these pitches to be successful.
In 2023, righties saw Miller’s four-seam 59% of the time, his Slider 32%, his Cutter 8% and his Changeup just 1%. Miller used his Four Seams in the zone for righties, where he got most of his excitement with the pitch. He used the Slider to work down and away from the right, and occasionally messed around with the front door switch as well. He threw his Knife to the right sides mostly when he was ahead in the count and threw it down and to the side. remaining time. I believe this was for the look of his out of hand Slider and Cutter as well as breaking both pitches. This allowed him to make hitters miss the pitch if they were looking for an out-of-hand slider. He only threw Changeup 3 times to righties, so not much to analyze there. On lefties, Miller reduced his Four Seam usage to 50%, and changed his cutter and slider to 25% and 15% usage, respectively. He also threw Changeup 10% of the time. Miller used the cutter heavily on the inside of the plate for lefties and kept the slider on the outside. He also left the lane a bit with the Slider to get some chases when he was ahead in the count. His tactics were the same with Four Seams as they were for righties, mostly staying in the strike zone.
In 2024, Miller went from starter to closer for the A’s, so he ditched his Cutter and Changeup and started using a mix of Four-Seam and Slider. Miller has thrown his Four-Seam to lefties 71% so far and his Slider 29%. He favors the Slider over the four-seam to righties, dropping it 55% versus the Four-seam’s 45%. An interesting thing I noticed is that he seems to throw 2 different Sliders, one to righties and one to lefties. His Slider on lefties stops off the glove a lot less than the Slider he throws to righties, and therefore drops a lot more because of it. So maybe Miller didn’t get rid of his Dritch completely, but instead killed the vertical movement to differentiate it more from his Four Seams so that he basically has a 3rd pitch that he can use exclusively for lefties. Miller didn’t throw his changeup much in 2023, but when he did throw it, he threw it to lefties. His changeup wasn’t a terrible pitch for him, and he got a 42.9% whiff rate with it, nearly double the league average. The reason he dropped the pitch is probably because he didn’t have the control it needed to make it useful, as he also only threw the Changeup in the zone 23.3% of the time in 2023. Some of that is designed to induce a chase, but he only did so on 13% of the Changeups he threw, so ultimately those pitches out of the zone weren’t effective.
Now let’s turn to Miller’s production and see if the changes he’s made have paid off for him and the A’s. In 2023, Miller produced above-average numbers of fly balls and line drives, but struggled to find success with Cutter, who produced a xwOBA of .379 in return. I hate to blame the failure of his Cutter on his complete lack of movement, as many pitchers have had success with gyro sliders that have no movement at all, but his cutter falls right between his Slider and the Four-Seam in his movement plot. on, which means it wasn’t different enough from the 2, in my opinion, and didn’t have enough glove break to give lefties trouble on the inside of the plate. His Four Seams also got hit frequently, with a .298 xwOBA against it on the year. I think this is because of the problem I mentioned before where his Cutter shape isn’t different enough, but it could also be because he was throwing four stitches. Miller favored the Four Seam in all but 0 counts. 2 last season, and even in 0-2 he still shot it 35%. I think he relied too much on the Four Seam, especially in counts where he was ahead when he didn’t need to give a great pitch to hit. These counts are where I think it would be nice to fit in more Changeups, which he didn’t really show much like I said before. His Slider performed quite well last season with a .207 xwOBA and a 47.1% whiff against it. His Changeup, while largely unused, had an average exit velocity of 92.6 mph.
This season, however, the script has completely flipped for Miller, whose Four-Seam is being struck at a 47.4% rate and only has a .197 xwOBA against it. Miller’s Slider has gotten better as well, with a 46.9% slugging rate and a paltry 0.076 xwOBA against it. I think the main factor in Miller’s improved performance is moving into a closer A’s role. Miller is now able to do what he does best in just a few at-bats, which is hold the four-seamer at the top of the belt and the slider is clipped off the right sides at the bottom of the belt or out. belt to lefties. As a starter, Miller had to add pitches to his arsenal that he either couldn’t handle or weren’t effective for him, such as the Cutter and Changeup, but now as a closer, he doesn’t have to worry : going through the lineup a few times and having to find different ways to get guys out because his 2 pitches are elite and that’s all he needs. It also helped add 2 mph to all of Miller’s pitches, as he now doesn’t have to worry about eating innings and can just empty the tank instead.
Mason Miller’s transformation from struggling rookie to dominant closer is a testament to his adaptability. By honing his craft with pitch design and optimizing his productivity by playing to his strengths, Miller has become a formidable force on the mound. While he continues to deliver great performances, Miller’s journey serves as an inspiring failure story, highlighting that success sometimes hides in plain sight. As the trade deadline approaches, his meteoric rise and impact on the A’s season will no doubt make him a sought-after asset.
