The Purple People Eaters, the Steel Curtain, and the Legion of Boom. In the NFL great defenses are a key to success and often elevated to a legendary status. Look no further than the Denver Broncos win this past Sunday to see the impact of a dominant defense. One of the most common phrases in football circles is "defense wins championships." But what about in baseball? Last week, Thomas boldly predicted that the Miami Marlins would be a top five defense in 2016. With such a successful defensive campaign in 2015, this is a prediction with which I wholeheartedly agree. But, this made me start to wonder, how often does defensive success translate to postseason success? If the Marlins have a top five defense next season, how likely is it that they make the playoffs? After looking at defensive stats from postseason teams between 2002 and 2015, the answer becomes clearer. Having a good defense is an important component of many championship caliber teams, but is not absolutely necessary.
I used a fangraph statistic called Defensive Runs Above Average, abbreviated as DEF, to analyze a team's defensive success. I will give you a brief overview, but for a more detailed explanation head on over to fangraphs and read their DEF tutorial. Essentially, DEF is a measure of a player's defensive success compared to league average. Importantly, there is a positional adjustment so that you can compare the defense of two players who play different positions. For example, Def can be used to compare the defensive value of a catcher to that of a second baseman. The formula given by fangraphs is:
Fielding Runs Above Average is another name for the metric Ultimate Zone Rating (UZR). UZR attempts to estimate how many runs a player gave up or saved on defense. A higher UZR essentially means a player plays better defense and therefore saved more runs. However, UZR is incomplete without a positional adjustment because certain positions are more difficult to play from a defensive standpoint. Therefore, DEF was developed because it removes positional bias giving you an idea of a player's and team's overall defensive prowess.
Is DEF a bulletproof statistic that tells the whole story? No, but it is an effective sabermetric stat to estimate how strong a team is defensively. DEF of each player on a team can be summed to determine its overall defensive success. A DEF value of "0," is considered average. For each season between 2002 and 2015, I ranked teams based on their DEF rating. Next, I determined the DEF rankings for each playoff team to determine how important a high caliber defense is to success.
The number of playoff teams that had top 5, 10, and 15 defenses based on their DEF rating can be seen in the chart below:
A total of 120 teams made the playoffs spanning the 14 seasons between 2002 and 2015. 75 of those teams had defenses that were ranked in the top half of the league, while 45 of the teams had defenses ranked in the bottom half of the league. Furthermore, on average, two teams with top five defenses made the playoffs each year. Some other interesting stats: the team with the number one defense made the playoffs in 8 out of 14 seasons, and the team with the number two defense also made the playoffs in 8 out of 14 seasons. Out of the 28 teams that made the World Series, nine had a top five defense and four of those won the championship.
It is important to note that bad defensive teams have also had success. From 2002-2009, a team with a bottom four ranked defense made the playoffs (the Yankees six of those times). The 26th ranked defensive team won the world series in 2011 (St. Louis Cardinals) and the 29th ranked defensive team won the world series in 2004 (Boston Red Sox). Furthermore, many mediocre defensive teams have performed well. However, this data still clearly shows that having a good defense contributes to success.
Now, am I saying that if Thomas' prediction is correct and the Miami Marlins are a top five defense they will make the playoffs? No, but it is certainly a step in the right direction. If the team is healthy, the outfield trio of Giancarlo Stanton, Christian Yelich, and Marcell Ozuna lives up to some of its potential, and the Marlins get another great year from Dee Gordon and Adeiny Hechavarria who knows what will happen? A strong defense can certainly help compensate for some (emphasis on some) below average pitching. Remember how all the "experts" were calling the Nationals a sure-fire World Series contender last season? Look how that turned out. We don't know what the Miami Marlins season will look like yet. Hold off on those predictions until we see some real baseball. Until then, let's dream.
DEF statistics were taken from Fangraphs.