The Effect of Fastball Velocity on the Slider

I’ve heard it said in the past that a batter should take care of the pitcher’s fastball first and then deal with the breaking ball. If this is true, then the faster the pitcher’s fastball is, the more the batter needs to be aware of the fastball when at the plate. I want to look at how this affects the most popular pitch in baseball: the slider.

First I calculated the average velocity of each pitcher’s fastball for pitchers who threw at least 100 fastballs (FF, FT, SI) in each major league season from 2017-2021. Based on the calculated average fastball velocity, I divided the pitchers into three groups: 143-148 km/h, 148-153 km/h, and 153-158 km/h. I then further divided the groups according to the velocity and movement of the slider thrown in each.

Then I calculated the Run Value/100 for each group. Let’s start with the velocity group between 143 and 148 km/h (click to enlarge). Read the rest of this entry »

Pitch Mix Variation and Ways to Measure It

Earlier this year, I took a hack at defining what I referred to as pitch mix variation. Pitch mix variation, as I conceived of it at least, would be a single number to capture how much any given pitcher mixes his offerings. A higher pitch mix variation (PMV) would indicate first that a pitcher has a relatively diverse mix of pitches and, second, throws each pitch roughly as much as any other. A lower PMV would indicate a pitcher has fewer pitches and relies on just one or maybe two of those the vast majority of the time.

Among other things, baseball types are quick to measure the quality of stuff, command, control, and the number of offerings of pitchers. That said, to my knowledge there doesn’t appear to be a standardized catch-all metric for how often those pitches are utilized. There also seems to be value for such a metric. For instance, a college starter might have a 3,000-rpm curveball that plays up in models, but if he doesn’t trust it and therefore throws it just ~5% of the time, that elite spin might somewhat belie long term bullpen risk.

Put simply, a pitcher who throws a four-seamer, sinker, curveball, and changeup all 25% of the time is quite possibly tougher to square up than one who throws just a four-seam (80%) and curveball (20%), all else held equal.

However, this post isn’t about assigning value or finding an optimal PMV (surely that depends on the individual pitcher), but rather juxtaposing various potential measures. To that end, this post will include the following: (1) a recap of the original formula and logic I previously cobbled together, (2) an overview of two more formalized models for quantifying variation, and (3) a comparison of those three measures across several hundred pitchers in 2021. Read the rest of this entry »

Weighted Runs Batted In Efficiency

Imagine that throughout high school, teachers gave their favorite students easier tests than the rest of the class. Results would be clear: the majority of the favored students would come out with stronger scores. However, one would question if those strong scores would be a result of high intellect or because of an easy test. Contrarily, there would be other students who would still score well while given a difficult test. Now there’s an issue. If the teachers want to know which of the students know the material the best, how should they figure it out? They know that they can’t take the highest score, because they are aware that the scores are not an accurate representation due to the skewed tests. This is the situation in which the RBI has put the baseball world.

When the RBI was first documented as an official statistic in 1920, the wording of the definition in Rule 86, Section 8 of the Official Baseball Rules was “The number of runs batted in by each batsman.” Although this definition was slightly vague, its intention was to quantify which batter is the best at batting in runs. For years, this statistic has been praised. The RBI is always one of the first statistics to be mentioned while summarizing a player’s year and career. The RBI is even in the most prestigious hitting award, The Triple Crown. Despite its strong reputation, over the last few years it has become clear that the RBI doesn’t answer “Which batsman is the best at batting in runs?” The RBI only answers “Who has batted in the most runs?” Although that may seem like a small wording change, the two questions are tremendously different. Read the rest of this entry »

Looking for a Breakout Performance

Every franchise is looking for that player who seems to come out of nowhere to be a major contributor in their lineup. Players like José Bautista, who went from 1.8 WAR in 2009 to 6.5 WAR in 2010, or Justin Turner, who jumped from 0.5 WAR in 2013 to 3.4 WAR in 2014. The cost for acquiring these players was affordable because they were no longer prospects and most of the league had written them off as potential everyday players.

If a team had the ability to identify which players are most likely to exceed industry expectations, they would have a significant advantage over their competition. That is why I decided to create a model that tries to identify potential breakout performers.


The first thing I needed to do was to define what constitutes a breakout performance. I thought of several different definitions, but I decided to define a breakout performance as any player that exceeded their career high WAR in a single season by at least 2.0 WAR. So if a player had recorded a season of 0.0 WAR, they would need to have at least a 2.0 WAR season. If a player had recorded a season of 1.0 WAR, they would need to have at least a 3.0 WAR season and so on and so forth. Read the rest of this entry »

Previewing the CBA Deadline

MLB’s Collective Bargaining Agreement (CBA) is set to expire on December 1st. Unfortunately with all of the disagreements over issues including rule changes, profit sharing, and minor league living conditions, it’s possible that we could see a work stoppage similar to the one we saw in 1994.

The MLBPA’s website says the purpose of the CBA “is to set forth their agreement on certain terms and conditions of employment of all Major League Baseball Players for the duration of this Agreement.” This is vital to the league and many other major U.S. sports because it sets fair and ethical rules for players and teams to abide by. However, owners have historically dominated negotiations and kept the lion’s share of profits. In recent years, players have been much more open to speaking out, and there has been significant pushback in the media. If there aren’t substantial changes made by December, it would not be surprising to see another lockout or strike.

If there is no new CBA by December 1st, MLB rules say major league play will stop until it is renewed and there will be no moves allowed by any club. This will play a significant role this offseason regardless of whether the CBA gets renewed or not, as the potential scare of a delayed CBA may force teams to rush moves or wait longer on them. Read the rest of this entry »

David Fletcher’s 2021 Was Missing Something

What’s 0/573?

Baseball Savant knows, but they also know it’s useless information. This is precisely why they do not display it. And it’s a shame that they don’t display it.

If they did, it would show that David Fletcher is in the zeroth Percentile for Barrels.

For a quick refresher, Barrels are “a batted ball with the perfect combination of exit velocity and launch angle.” To qualify, a ball must be hit at least 98 mph. For that exit velocity, a launch angle of between 26-30 degrees is required. For every single mph increase, the range of acceptable launch angle degrees increases by two or three, up until 116 mph. At that level, any ball hit between 8-50 launch degrees is considered Barreled.

Fletcher didn’t do that once in 2021. Instead, he mustered eight “close calls” among his 573 batted ball events. Read the rest of this entry »

Giving Away At-Bats

One piece from FanGraphs this season has stayed with me more than any other article on the website. In early September, Kevin Goldstein wrote a piece called The Rays’ Unique Ability To Mitigate Risk.

For most of the piece, Goldstein examined why the Rays pitch effectively even though they use so many relief pitchers. Most of the time, a team that cycles though relief pitchers in bunches is a bad one, like the Baltimore Orioles this year. But the Rays, as they often do, defy common practice.

I actually did not remember that part of Goldstein’s article; I only remembered it when I re-read it before writing this. What stuck with me was a short section at the beginning in which he explained why the Rays score so many runs.

Goldstein’s question was how does a team that has no high-priced free agent slugger, like Bryce Harper or Manny Machado, or no home-grown young stud, like Juan Soto or Fernando Tatis Jr., score so many runs? (You will see in a moment why I am ignoring the Rays’ young phenom Wander Franco.) Read the rest of this entry »

Pitchers Had Another Bad Year Hitting. But No. 9 Hitters…

October 4, 1972: Yankees righty Larry Gowell hits a double off of Milwaukee Brewers pitcher Jim Lonborg. The American League Brewers played that game in an American League park in the Bronx, with no designated hitter on either side.

October 3, 2021: Dodgers righty Andre Jackson hits for himself, in relief, grounding out against Milwaukee Brewers pitcher Daniel Norris. The National League Brewers played that game in a National League park in Los Angeles, with no designated hitter on either side.

Gowell started his game and went five innings. In the third he led off, got his double, and advanced on a 6-3 groundout before being stranded at third base. In the bottom of the inning, he gave up a sac fly to John Briggs. That proved to be the only run, tagging Gowell with the loss.

Jackson was in relief of Phil Bickford, himself in relief of Walker Buehler. When a reliever hits for himself, rarely is the game competitive: here, Jackson had already pitched two innings with a nice lead. Immediately before Jackson’s spot in the batting order came up, outfielder Matt Beaty drove in catcher Will Smith, utility man Chris Taylor, and himself. Dodgers skipper Dave Roberts surely saw the score in LA, the score in San Francisco, and Jackson’s roster status for the playoffs, and let him hit and finish out the ninth. (Jackson collected a save for his three-inning effort, the first of his career.)

Gowell probably wasn’t the last AL pitcher to bat before the DH. The Angels and Royals had night games on the same day with pitcher at-bats in the Pacific and Central time zones. If baseball should adopt the designated hitter rule for the National League effective next year, Jackson will probably be the last NL pitcher to bat under these rules. The Reds’ Reiver Sanmartin collected three at-bats before being lifted for a pinch-hitter on the same day, but two of those came to start and end the fifth inning in his game against the Pirates. The Giants’ Logan Webb collected three at-bats too, but his day as a batter ended after a home run in the fifth. All those games began around the same time, so Jackson’s appearance in the eighth inning was a bit later on. Read the rest of this entry »

Frankenstein and the Rays’ Sister City Concept

In 2018, the Tampa Bay Rays introduced the Opener, a novel concept in which a relief pitcher started a game with the purpose of shutting down an offense in the first few innings. The Opener would then hand the ball to a bulk pitcher, who went three-to-four innings before giving way to the usual bullpen corps.

When the Rays introduced the Opener strategy, many in baseball thought it was blasphemy. Starting pitchers have roles and this is the way the pitcher order has been for generations. How dare the Rays upset the natural order of roles, titles, and statistics?

When analysts looked at the Rays roster, however, they quickly understood what the team was doing. By not recognizing a “pitching rotation,” the Rays were looking a level deeper. They were stacking pitchers on a per-game basis, with the intent to win each game and hence build enough wins to make the playoffs. Once it was understood, the Opener was applauded and eventually copied throughout the league.

Besides being a sly way to neutralize lineups, the Opener represented the “Rays Way” amidst financial necessity. The team could not afford a typical major league rotation of four or five quality starters. Relief pitchers are cheaper and easier to find. They couldn’t find five aces, so they built ace performances using multiple relievers, with the additional bonus of paying them less. If you can’t find a hundred-million-dollar starter, build one. Read the rest of this entry »

Should Boston Prepare To Move Past Christian Vázquez?

As the Red Sox move on to the American League Championship Series, the team may not have the talent to contend with teams like the Astros. Some could say the same thing about the Rays, but the Red Sox were fortunate Tampa Bay’s staff was shot after injuries plagued them throughout the season. The Red Sox have All-Stars talents like Rafael Devers, Xander Bogarts, and J.D. Martinez, but they need better role players who provide depth in October if they are truly going to contend each year. Successful teams don’t often undergo a complete rebuild, instead choosing to go through mini-rebuilds and focus on positions of need. This avoids 70-win seasons, ​​something Boston sports fans have not been accustomed to in the last two decades. It is no mystery that they need pitching help, but a more overlooked position of need is at catcher, which could help improve the staff as well.

Boston’s primary catcher and recent hero, Christian Vázquez, has had many memorable moments, none more important than his walk-off home run on Sunday. Despite this, it may be time for the Red Sox to part ways with their veteran. At age 31, Vázquez has shown signs of aging this season, and the Red Sox know this too. In the Wild Card game against the Yankees, the biggest game of the year, the Red Sox turned to backup Kevin Plawecki to get the job done behind the dish. Similarly on Sunday, Plawecki got the start while Vazquez came in to pinch-hit. The Red Sox need to start planning for their long-term future, which means seriously considering their better and younger options at catcher. Read the rest of this entry »