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."...read the rest of this article on Guy Speed.