How Important is Luck in Baseball?
Luck plays a large role in the outcome of baseball games, and how players are perceived by fans.
To this day, many New York Yankees fans still gleefully speak of Aaron Small, who despite owning a 5.49 ERA (and 82 ERA+) from 1994 to 2004, somehow rolled out a 3.20 ERA and 10-0 record as a 33-year-old with the Bombers in 2005.
Even though some parts of Small's memorable season were legitimate (i.e. 133 ERA+)--and his 76 innings were a pretty small sample size--the journeyman also got extremely lucky. First and foremost, his high win total was a direct product of the Yankees powerhouse offense. In 2005, the Yankees produced the second most runs in the major leagues (886), jacked the second most home runs (229), and posted the second highest OPS (.805).
And while the Yankees scored an already impressive 5.46 runs per game, when Small was on the hill, the team provided a whopping average of 7.41 runs. With flush run support like that, even if Small had posted an ERA more in-line with his career rate, he likely still could have won just as many games.
The right-hander was also particularly lucky with keeping runners off the base paths. Despite owning a career .330 BABIP (league average sits around .295-.300), Small posted a far reduced .273 rate in 2005. Small's almost 60-point BABIP drop off was a major factor in his uncharacteristically low hit rate, which went from a lofty career 11.0 Hits/9 to an aspirational 8.4 rate. But perhaps more importantly, Small's rate of ground balls didn't increase. Prior to 2005, Small owned a 0.88 GB/FB, yet in 2005, he posted an identical 0.82 GB/FB.
"If your BABIP is really low, compared to the league [or one's career] average, and you're not getting a lot of ground balls--you're beating the statistical odds," said Rick Peterson, the Director of Pitching Development for the Baltimore Orioles. "It can't last over time. It's impossible."
Peterson, a long time major league pitching coach, also founded 3P Sports, which is a baseball academy based on utilizing biomechanical data to dissect and help fix pitchers' mechanics. The clinic is particularly focused on adjusting mechanics to force pitchers to pound the bottom part of the strike zone. While Small didn't necessarily undergo a mechanical change prior to 2005, Peterson feels that a pitcher's "luck" could change for the better with an altered approach.
"[In 2010, Milwaukee Brewers pitcher Yovani Gallardo] had a delivery that would not allow
him to get to the bottom of the strike zone," said Peterson, who was the Brewers pitching coach from 2009 to 2010. "[Gallardo] had about 38% of his pitches in the bottom of the strike zone, and [his BABIP] there was about .160. [...] [After working with Gallardo], he was actually able to increase [his pitches in the lower zone] by about 15%. And he ended up going to the All-Star game."
And while Peterson admitted to being a "big sabermetrics person," he also mentioned other factors that have yet to be fully fleshed out by advanced statistics.
"The reason why Pedro Martinez and Barry Zito were so successful was because hitters would mishit the ball constantly," said Peterson. "[Opposing hitters] did not center the ball on the barrel of the bat. A lot of balls were hit on the hand and end of the bat. [...] [Sabermetricians] will probably [be able to measure point of contact] in PITCHf/x data [in the future], but I don't think there's any data [right now] that indicates that."
On a smaller scale, Peterson additionally acknowledged that swings and misses play a key role in the success of a pitcher. Per Aaron Small, the pitcher only struck out batters at a 4.4 K/9 clip in 2005 (versus career 5.0 K/9), and the usually walk-heavy hurler only allowed 2.8 free pass per 9 (versus career 4.2 BB/9). His lack of whiffs and new found control skill set continued to make his success dubious.
Yet, the legend of Aaron Small ended almost as soon as it started. The following season, in 2006, Small posted a dismal 8.46 ERA (54 ERA+) over just 27.6 innings, in what would be his final season in baseball.
As extreme an example as Small might seem like, the luck factor affects even the most mainstream of players in the game too. For instance--on the surface--Tampa Bay Rays stud David Price, who owns a career 3.16 ERA (and 124 ERA+), has hurled a putrid 5.24 ERA (and 75 ERA+) over his first 55 innings so far. Perhaps his poor start to 2013 is due, in part, to his recent strained left triceps injury--but the pitcher has also been extremely unlucky. Despite owning a career .277 BABIP, Price has rolled balls at an elevated .345 rate. In addition, his 3.53 xFIP is 1.71 points lower than his ERA. And, as according to Brooks Baseball, considering Price's .333 lower zone BABIP more or less mirrors his .365 upper zone BABIP, the ace might have a bit of an uphill battle once he comes off the disabled list.
The good news for unfortunate cases like David Price is that, given his track record (and talent), the baseball Gods will soon be back on his side; reverting his surface statistics a little bit closer to his peripherals. But for anomalies like Aaron Small, he's just lucky to be forever known as a "folk hero" in New York.