Quantifying the Rays’ incredible defense


The past few years, the Tampa Bay Rays have been known as an outstanding defensive team. But just how good are they? Let’s look at some stats (progressing from simple to very technical) to see just how good the Rays’ defense was in 2011 compared to the rest of baseball.

Fielding percentage is a misleading stat because it’s the percentage of plays a player (or team) makes divided by the percentage of plays he (or the team) made plus errors. It doesn’t tell you anything about the overall percentage of plays made when the ball was hit in that player’s direction. Nevertheless, it’s a decent indicator of how sure-handed a team is on defense. By the metric of fielding percentage, the Rays were tied for the best in baseball in 2011 at .988. The league average was .983, so the Rays were .5% better than average, and they were 1% better than the MLB-worst Cubs. That may not seem like that big of a difference, but that’s a difference of 28 errors over the course of the season compared to the average of 60 errors compared to the Cubs. That many errors certainly impact ballgames, and if the Rays had made as little as one more error, they might have been forced into a one-game playoff at the end of the season. All the errors they negated made a big impact. According to another similar stat, defensive efficiency rating, the percentage of balls in play that fielders turned into outs, the Rays were tops in baseball by quite a bit, ranking at .724 compared to the league average of .694 and the second place Reds at .705.

Let’s talk a little bit about runs saved, in which there are various metrics. In Rtot and Rtot/yr, both measures of runs saved compared to average, the Rays ranked third in baseball. Their Rtot was 36 compared to the league average of 2, and their Rtot/yr was 3 compared to the league average of 0. That’s certainly good, although 3rd seems a little bit low for the Rays. According to another measure though, Baseball Info Solutions’ Defensive Runs Saved (above average), the Rays were tops in baseball by a wide margin, registering at 83 compared to the league average of 0. Even the second place Angels were 30 runs away at 53. Although according to Baseball-Reference’s dWAR (defensive wins above replacement), the Rays were just 3.9 defensive wins above average, third in baseball once again. It’s clear that the Rays are a very good, even elite defensive team. But where is the “wow” factor that makes you know that the Rays are really a cut above the rest?

We go to Fangraphs’ UZR (ultimate zone rating), which compares each fielder to his peers to his position in order to record runs saved. The Rays’ UZR comes in at an impressive 53.9 rating, second in baseball to the Arizona Diamondbacks and well above the league average of -0.04. In terms of UZR/150, which is runs saved per 150 innings, the Rays were the best in baseball, coming in at 8.8 compared to the second place Angels at 6.7 (the D-backs were at 6.5) and the league average of .06. Those are both impressive, but again it’s nothing that indicates that the Rays are really far and away the best in baseball. So let’s get a little bit more technical.

BAbip is batting average on balls in play, a player or team’s batting average once they put the ball into play, taking out strikeouts and home runs and adding in sac fly to the traditional batting average formula. By that metric, the Rays are undoubtedly the best in baseball. When a ball was put into play in 2011, overall it had a 29.5% chance of being a hit (.295 BAbip). For the Rays, it was a different story. Rays pitchers had the luxury of knowing that when they allowed a ball in play, it only had a 26.7% chance of being a hit (.267 BAbip). The Rays pitchers certainly contributed to that, allowing a 17% line drive percentage compared to the league average of 18%, but even the Angels’ whose dominant pitchers allowed just a 16% LD%, allowed a .285 BAbip. That illustrates the great advantage that the Rays get from their defense.

And this makes it even clear. FIP is a fielding-independent pitching, a stat that estimates ERA using only the aspects that pitchers can control: home runs allowed, walks (and hit by pitches), and strikeouts. What’s interesting is to compare FIP to ERA. In general, if a pitcher has good luck his ERA will be lower than his FIP and if he has bad luck, it will be higher. But when you look at team FIP and ERA, most of the luck is canceled out and you really get to see how good the team’s defense is. The league ERA was 3.94 and the league FIP was 4.04, so in general the league was a little bit lucky. But there was a much bigger difference between FIP and ERA for Rays pitchers. Rays pitchers had a great 3.58 ERA, tied for 7th in baseball. But their team FIP was actually 4.03, just a tick below the league average. The difference between their team FIP and their team ERA was -0.45. There was no bigger difference neither upwards or downwards for any team in baseball, and the league average for difference between FIP and ERA was .001. That shows that the Rays defense is clearly superior. Their pitcher’s consistently performed a half-run better than their FIP’s, and it was no coincidence. The Rays have posted ERA’s .3 or more lower than their FIP’s three of the past four years. The Rays’ great defense makes their very good pitching over the top. And it keeps them in the playoff mix every single season even when their bats are struggling. The Rays’ defense in 2011 was clearly the in baseball. And they’ll look to keep that stout defense up in 2012 and beyond as the hope to progress from a fringe-playoff team to a perennial championship contender.