Image: (Jason Allen/AP Photo)
Contributors: Ryan Borkowsky, Nate Carlson, Daniel Buckholz, Daniel Junyeong Shin, Kaj Desch
What is Slider Run Value?
Baseball Savant’s slider run value appears to be a rather self-explanatory statistic. The higher the value, the better the pitch, or the more positive impact it brings to the team. But its calculation necessitates a higher degree of complexity. The run value of a pitch is based on the extent to which it changes run expectancy, or the probability of a run being scored in a game scenario, factoring in the count, the amount of outs, and the runners on base.
For example, in 2022, with no outs and the bases loaded, there were an average of 2.3 runs scored from that point until the end of the inning across all MLB games. Often the run environment is taken into account, which factors in the ballpark, whether the game is high scoring or low scoring, and even the weather of a specific day.
Furthermore, each individual pitch either adds or subtracts from run expectancy. A 3-2 ball will increase the run expectancy of the inning, while a strike will decrease it. Yet, not all 3-2 pitches are made the same; a 3-2 strikeout with the bases loaded and two outs will have a more negative run value than a 3-2 strikeout with the bases loaded and no outs. This decrease in run expectancy would be attributed to the pitcher, the value of this decrease being subsequently added to the run value of whichever pitch was utilized.
This list was not conducted strictly following the slider run value leaderboard; some other pitchers who will not be discussed but had highly graded sliders last year were Dylan Cease, Andres Munoz, Ryan Helsley, and Reynaldo Lopez.
The sliders that these next pitchers possess include, but are not necessarily limited to, the devastating, high-spin-rate wipeout pitches that make batters look as if they are swiping at a pinata while blindfolded. Put simply, these pitchers’ sliders were the most effective at helping their team win.
Starting Pitchers:
Chris Sale, ATL (24 slider run value)
Nate Carlson
Chris Sale has built a prolific MLB career off of his slider, so it’s fitting that he tops this list, especially following his Cy Young campaign in 2024. No doubt a byproduct of his Hall-of-Fame level pitch and funky delivery, Sale finally earned the award he had surprisingly not yet obtained.
Drafted 13th overall to the Chicago White Sox out of Dunk City in 2010, Sale only pitched in 11 minor league games before getting his big league call-up. In August and September of that same year, Sale dominated with 32 strikeouts in 23.1 innings of work and a 225 ERA+. After another strong year of relief in 2011, Sale was promoted to the starting rotation in 2012 and embarked on what would become a seven year run of all star games appearances (including 3 starts), Cy Young votes, and even MVP votes in four of those seven years. In these seasons he played for both the White and Red Sox, as he was traded for Micheal Kopech and Yoan Moncada following the 2016 season.
After starting Game 1 of the 2018 World Series for the Red Sox and closing out game 5 to bring it home, Sale earned his World Series ring and looked more than set on a hall-of-fame trajectory. Unfortunately, injuries became the dominating narrative for Sale following this season, as in a 5 year, 145 million dollar extension, he would miss most to all of 3 straight seasons from 2020 to 2022 mainly due to Tommy John Surgery.
A return to the mound in 2023 was refreshing for Red Sox and MLB fans alike, but it certainly wasn’t as magical as it used to be. Sale threw is 4-seam fastball 43% of the time despite a run value of just 3 and declining velocity, compared to his dominant seasons of 2017 and 2018 where he threw it 37% and 39% of the time for run values of 27 and 13 respectively. It also likely didn’t help that he allowed a pulled fly ball rate of 17.9% while calling Fenway Park home. Finally, his ERA was a career high mark at 4.30, despite xERA of 3.63, so his issues could be partially attributed to bad luck.
Chris Sale closes out the 2018 World Series
Perhaps the Braves had the foresight to pick up on these issues, so the Red Sox dealt Sale to them for quad-A shortstop Vaughn Grissom. Buying low on a pitcher like Sale could never be frowned upon, but I think his performance surprised everyone. Sale’s Triple Crown season of 18 wins, a 2.38 ERA, and 225 strikeouts utterly trashed Major League hitting and blew away the competition for the National League Cy Young, and it was all on the back of his slider.
His most frequently thrown pitch at 40.3%, MLB hitters facing it batted .171, slugged .236, whiffed 42.7% of the time, and only hit it hard 21.7% of the time. His arm angle came down to 11 degrees, which is lower than his previous 3 years, and he maintained both horizontal and vertical breaks above league average with the classically lower velocity. All of these put together creates a storm of success, and to uphold this proficiency across 1,135 pitches in 2024 was a sight to behold.
Ronel Blanco, HOU (17 slider run value)
Daniel Junyeong Shin
Ronel Blanco, a Dominican right-handed pitcher, began his professional baseball career in 2016, signing with the Astros as an international free agent with a $5,000 signing bonus at the age of 22. Despite having a mediocre couple of seasons after his debut in 2022, Blanco emerged as a breakout player in the 2024 season, where he recorded a 13-6 win-loss record with a 2.80 ERA in 167.1 innings pitched, leading the American League with 6.13 hits allowed per 9 innings and .190 opponent batting average. With a no-hitter against the Blue Jays on April 1st, 2024, Blanco won the Astros’ Pitcher of the Year award after the season.
Blanco’s pitch arsenal relies on fastballs, curveballs, sliders, and changeups. Compared to 2023, he decreased his slider usage from 48.6 to 30.2%, while increasing changeup (9 to 22.1%) and curveball (2.2 to 9.4%) usage. His slider was the most effective pitch, recording a +17 run value, with the opponent slash line of .180/.230/.284 and a .228 wOBA against it. The slider had a 6.8 extension, ranking top 20% in the league.
However, the pitch showed some underlying statistical backslides compared to 2023. The spin rate dropped from 2149 to 2091 RPM and the average exit velocity increased from 83.4 to 86.3 mph. The whiff rate declined from 42.6 to 33.3%, the put-up rate fell from 21.6 to 19.4%, and the K% decreased from 28.1 to 23.8%. Other metrics like xBA, xSLG, and wOBA showed an increase compared to the previous season. The slider’s hard-hit rate reached 31.9%, with its vertical movement of 5.9 inches and horizontal movement of 2.1 inches below the league average. The average pitch velocity, 86.4 mph, was slightly faster than the league slider average, 86 mph.
Such data raises questions about Blanco’s slider’s effectiveness. Yet, his slider run value led the American League. What made the slider so effective?
The answer lies in tunneling. The poor vertical and horizontal movement leads to better tunneling, where different pitches appear identical to the batter during their flight to the home plate. This leads to poor contact, as shown in the 6.13 hits allowed per 9 innings. The first and second pictures are respectively right-handed and left-handed batter’s points of view. The slider release point (6.0) is consistent with the fastball (6.2), changeup (6.1), and curveball (6.2) release points, making it difficult for batters to differentiate from other pitches in the early trajectory.
For both types of batters, the recognition and commit points of slider and changeup appear to be almost identical, meaning that both right and left-handed batters face similar challenges in distinguishing and reacting to sliders and changeups before committing to their swings. Moreover, a 45% active spin rate suggests that Blanco’s slider relies on deceptive qualities rather than dominant physical characteristics.
Joe Espada, the manager of the Astros, stated “His fastball, slider, changeup all look the same until the ball enters the zone. Hitters are committed to that one pitch and, all of a sudden, he’s either going below the zone with the change-up or away from the barrel with the slider.” Additionally, a low BABIP of .220 and suspicions of foreign substance usage, where he received a 10-game suspension last May, may have contributed to his effective pitching repertoire.
Although Blanco showed dominance on the mound, his 10.1% walk rate in 2024 was the highest mark among all qualified starters. Also, his 4.00 xERA, 4.15 FIP, and 4.09 xFIP suggest that his 2024 season may have relied on the Astros’ defense and luck. His long-term success relies on improving his control and maintaining deceptive qualities of pitches.
Logan Gilbert, SEA (10 slider run value)
Ryan Borkowsky
Drafted 14th overall by the Mariners out of Stetson University in 2018, Logan Gilbert entered his 2024, age-27 season after establishing himself as one of the more reliable pitchers in the AL. He had provided the increasingly-rare reliability his past two seasons, pitching 185 innings in 2022 and 190 in 2023, only to surpass both of those marks with 208.2 in 2024.
After his 2022 sophomore season where he pitched to a 3.20 ERA as a 25-year-old, many projected him to take a leap to becoming one of the league’s aces in 2023, yet his ERA regressed to 3.73 – not bad by any means, but not quite ace-level. In 2024, though, he returned to his 2022 numbers, posting even more dominant underlying statistics.
His ERA was 3.23, slightly higher than his 2022 marks, yet there were plenty of signs that his numbers should have been even better than that; Gilbert walked less people (lowest BB% of his career) induced the most ground balls of his career, the least line drives and fly balls, struck out the most people of his career, and induced the lowest hard hit% of his career. All of these underlying improvements actually lead to his expected ERA being 3.14, fourth-lowest in the league and lower than his actual ERA. For reference, his 2022 xERA was 4.11, a year where he had a lower ERA than 2024, indicating improvement beyond what the face value statistics like ERA suggest.
His 2022 ERA being below its expected mark may partly be due to T-Mobile Park being a pitcher-friendly stadium, keeping in hard-hit line drives or fly balls, benefitting his statistics. In 2024, his league leading WHIP of 0.89 indicates that Gilbert’s results were actually worse than what many of his underlying statistics would suggest.
Integral to his dominance was his most-used pitch, his slider, which he threw 32% of the time. This is a jump from 2023, where he only threw it 29.7% of the time, while he threw his fastball 41.8% of the time; he made his slider his featured pitch in 2024, reducing the fastball usage to 30%. This paid dividends, as the whiff% on his slider jumped up from 32.2% in 2023 to 36.8% in 2024. His slider utilizes gyro movement, meaning in dives late, without much horizontal break. Its movement profile is supposed to be at the origin of the X-Y movement profile graph on Baseball Savant:
This slider movement profile was established in his 2023 season, but he seemed to have gained more confidence in it in 2024, increasing its usage and using it in tandem with his fastball, making it much more effective.
A gyro slider differs from the standard slider, a pitch that usually has an element of horizontal break to it. This allows Gilbert’s slider to appear as if it is a fastball until very late, fooling the batter with its apparent dive and lesser velocity. Gilbert’s tunneling of these two pitches is evidenced in his nearly equal usage of fastball and slider, one of his 2024 innovations that contributed to his success. This results in a lot of ground balls, seen in its 54.7% GB rate, as batters swing over it, expecting the apparent “rising” movement of a fastball.
Zack Littell, TB (9 slider run value)
Daniel Buckholz
Zack Littell was on my fantasy team last year. He is a pitcher for the Tampa Bay Rays. Zack Littell is fine, a solid pitcher. I’m being told he used to pitch for the Giants, and the Twins. This is news to me. I always thought he was someone the Rays had pulled out of the ether in 2023. That’s fine, though. I’m open to new information.
Zack Littell throws a slider. He throws it an awful lot. More than any of his other pitches, in-fact. Littell’s slider comprised 39.9% of the pitches he threw last season according to Fangraphs. Overnight the Rays have turned his slider from kinda bad into a rather effective pitch, because it is what they do. Who is Edwin Uceta? Exactly.
Littell’s slider is odd, because it lacks vertical and horizontal breaking action compared to similar pitches. Littell’s slider appears out-of-place with the names about him on the leaderboard, as it utilizes gyro movement, operating more on subtle deception than massive amounts of horizontal break. Littell got hit around considerably more than his fellow slider savants, allowing a .257 batting average and .427 slugging percentage when throwing the pitch.
Relief Pitchers
Ryan Walker, SFG (12 slider run value)
Daniel Buckholz
Ryan Walker continues a treasured baseball tradition. That of the dominant reliever who seems to appear out of thin air (if you tell me you knew who Cade Smith or Porter Hodge were before last season I will not believe you). Walker showed promise in his first big league season in 2023 before delivering on that promise in a big way in 2024. The 29 year old right-hander appeared in a staggering 76 contests recording a 10-4 record (14 decisions as a reliever??) with a 1.91 ERA and 99 strikeouts. He also lowered his BB/9 from 3.52 down to 2.03.
It was a milestone year for Walker as he took over closer duties towards the end of the season (recording 10 saves) and figures to keep that role for the Giants heading into the 2025 season.
It’s easy to see why Walker makes this team. His slider doesn’t have elite vertical break, but it does have a mind-breaking 14.9 inches of gloveside horizontal break. When throwing his only breaking pitch in 2024, Walker held batters to a .157 batting average, as well as a 38.0 whiff% and a similar 38.7 K%.
Hunter Gaddis, CLE (10 slider run value)
Kaj Desch
Hunter Gaddis is a right-handed relief pitcher for the Cleveland Guardians, entering his 4th year in the majors. He posted a spectacular 1.58 ERA in 2024 with 78 appearances out of the bullpen, recording 66 strikeouts and only allowing 4 home runs.
He primarily appeared during the 8th inning as the setup man to Emmanuel Clase, and was a key reliever in Cleveland’s postseason run, despite giving up a backbreaking go-ahead 3-run homer to Juan Soto in Game 5 against the Yankees. He will most likely remain in that role while Clase remains with Cleveland.
Gaddis’s slider represented 44.8% of the pitches he threw last year, and it was incredibly effective, with 5.1 inches of break. With his slider, he held batters to a .163 average, and induced a whiff percentage of 30.7%. It was additionally an improvement over previous years with a 5.5 mph increase in slider velocity. He stated that he wanted to think less and just throw hard on the mound, and his adjustments have been very effective.
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