June 22, 2012

Raising Aces

A Slide Step in the Wrong Direction

by Doug Thorburn

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The classic Greek sabermetrician Plato said that “necessity is the mother of invention.” True to form, the slide step was borne from the need to suppress stolen bases at a time when the game was experiencing a record surge of thievery, but I submit that the strategy carries heavy costs that fail to outweigh the perceived benefits. The slide step invention is in dire need of an intervention.

The slide step is an artifact of the 1980s, a time when players such as Rickey Henderson and Vince Coleman were surpassing 100 stolen bases with regularity, terrorizing pitchers with constant distractions on the base paths. Since the Dead Ball Era, there have been 18 player-seasons that surpassed the 80-steal threshold, and 15 of those performances occurred in the 10-year stretch from 1979—1988. Henderson and Coleman were the last players to accomplish the feat, having tallied 174 steals between them in the '88 season, and were responsible for 10 of the 80-steal seasons between them, but the base-swiping explosion was hardly a two-man show (see accompanying chart). Today's top rogues of the base paths typically top out around 60 to 70 steals, with Jose Reyes' 78-steal tally of 2007 sticking out like a hitchhiker's thumb on the decade's SB leaderboard. For example, Michael Bourn has led the National League in stolen bases for three straight seasons, though his career-high is “just” 61 steals (accomplished twice). As Henderson told Harold Reynolds after the Mariner second baseman stole 60 bags in the 1987 season, “Rickey stole 60 at the break!”

The above chart covers the past 40 years of base-stealing, detailing the ascension of the steal throughout the 1970s that precipitated the spike of the 1980s. The steal lost momentum as focus turned to the long ball, and league-wide rates have stayed below one steal attempt per game since 2000. Even at the peak of the Speed Era, teams maxed out at just 1.21 steal attempts per contest, yet major-league pitching coaches opted to have their pitchers alter their mechanics for dozens of deliveries per game in order to create an advantage on a single pitch.

The typical big-league pitcher spends about two-fifths of his time in the stretch. In 2012, pitchers have registered 43.6 percent of opponent plate appearances with men on base, with 36 percent coming in typical slide-step situations—with runners on first and/or second base, or with runners at the corners. These situations will often comprise the most crucial pitches of a ball game, with runners on the bags threatening to score, and the first question that comes to mind is why a coach would want to undermine his pitcher's core skills under such critical circumstances.

The cost of a misplaced pitch skyrockets with men on base, where a homer puts crooked numbers on the scoreboard, yet the commonly accepted practice is to sacrifice pitcher mechanics in order to give the runner a lower chance of success on a steal attempt that may never materialize. A pitcher can shave one- to two-tenths of a second with a slide step, which is a significant distinction, as the same time frame separates a catcher with outstanding “pop” times from one who is merely average. Of course, a quick delivery can be mitigated by poor execution by the catcher, a misplay by the infielder, or a great jump by the base runner. Further, all of that effort can go for naught when a player has the raw speed of a demon like Billy Hamilton*, where the guy can beat a throw under ideal conditions.

*In this case I refer to Billy the Younger, who plays in the Reds' minor-league system and is currently running like a man possessed. He is not to be confused with Billy the Elder, whose 914 career steals place him third on the all-time list, due in part to six seasons of 80-plus thefts during the late 1800s.

Two-tenths of a second may not sound like much, but it represents a substantial adjustment with respect to pitcher timing. The entire pitch cycle takes place in less than two seconds, and the average MLB pitcher will reach foot strike between 0.95 and 1.05 seconds. A slide step can shave up to 20 percent of the time off of a pitcher’s delivery into foot strike, wreaking havoc on the timing and sequencing of the related links in the kinetic chain. It is common to see slide-stepping pitchers who fail to find their release point on the first few deliveries from the stretch, as the lower body reaches position before the upper body is ready to fire. The result is often an under-rotated pitch that misses high and to the arm-side of the intended target, which is a sure-fire recipe for falling behind in the count or hanging a hittable pitch. I shake my head when a pitcher uses a slide step with late rotation, only to watch the base runner score on a slow trot thanks to a two-run bomb on an elevated fastball; I then wonder how many runners the pitcher will have to personally catch stealing in order to compensate for the mistake pitch.

I spill a lot of digital ink on the subject of pitcher timing and its importance in pitch execution, and the difference between the stretch and the windup is one of the biggest obstacles in the developmental pathway. Many major-league pitchers are excellent from the stretch, with some exhibiting even better mechanics than when pitching from the windup, including greater momentum and earlier initiation of forward movement. There are hurlers whose timing is better from the stretch as well, though such is rarely the case for those who employ the slide step. The technique does not ensure a quick delivery, as I have seen some slide steps that were slow to the plate as well as some chest-high leg lifts that were exceptionally fast.

A consistent pitcher will display very similar timing from both windup and stretch, with early initiation of solid momentum and the appropriate pace into foot-strike to allow the shoulders to fire in sequence. A player will struggle to harness his stretch mechanics when there is a blatant timing disparity from his windup, particularly for low-momentum hurlers who utilize a slide step. We studied the issue extensively in our research for Arm Action, conducting experiments with individual players to study the functional implications of the slide step, and the results underscored the relative costs of rushing the delivery with runners on base.

There are pitchers who have mastered the slide step to the point of reaping the time-based advantages without sacrificing effectiveness. These are typically veteran hurlers who have learned how to effectively employ a second time signature, though a developing player will have a much harder time adapting his motion to two drastically disparate deliveries. Some crafty vets will use the slide step selectively from the stretch, mixing in various techniques from pitch to pitch to keep a runner guessing. I applaud those pitchers who have harnessed the slide step without sacrificing pitch command or stuff, though I question the utility of spending valuable development time on such an archaic tactic.

This line of thinking does not absolve pitchers of the responsibility of restricting the running game, but there are other ways for pitchers to have an impact in that area without screwing with their mechanics. Rather than disrupt the crucial element of pitch execution, a pitcher can help to thwart would-be base-stealers by keeping them chained to the bag through an effective pick-off move. A pitcher does not necessarily have to generate outs with his pick-off, because a good move can shrink the baserunner's lead and potentially delay the jump, creating similar ramifications as a slide step.

The physical delivery of a pitch is the most fundamental aspect of the game, and everything that follows on the field is an extension of that one event. One would need a damn good reason to intentionally alter a pitcher's delivery in a way that could suppress his skills, and it occurs to me that preventing one player per game from gaining one extra base falls far short of the cost-benefit threshold that would be necessary to justify such a modification.

The success rate of stolen-base attempts is higher over the past five years than at any other time in the 40-year span that we have under the microscope, and rates have been increasing steadily since the early 1970s. 20th-century sabermetrician Albert Einstein defined insanity as “doing the same thing over and over again and expecting different results,” and pitching coaches would have to be crazy to perpetuate the slide step in the face of such data. It is my contention that most pitchers would do better if they both A) went faster from the windup, and B) kept their natural leg lift from the stretch. Pitch execution is the single-most important facet of every play on the diamond and the epitome of the phrase, “baseball is a game of inches.” It is therefore insane to continue throwing a wrench into 40 percent of a pitcher's deliveries in an attempt to stop a once-per-game occurrence for which the pitcher is only fractionally responsible.

Doug Thorburn is an author of Baseball Prospectus. Follow @doug_thorburn
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