The Importance of Defense
One of the things we’ve been talking around, but have never said outright, really, is how wrong we used to be about the importance of defense. The statistical community, 5-10 years ago, believed that defense was a very minor factor in the game, and that you could evaluate the worth of a player by looking at his offensive line, and then making a minor adjustment for defensive value. Players like Darin Erstad and Rey Ordonez became sabermetric whipping boys as the main analysts of the day railed on the franchises that gave them playing time that they apparently didn’t justify through their at-bats.
However, as we’ve begun to come up with ways to quantify defensive performance, at least at a blunt level, we’ve realized that we were wrong. Badly wrong. Defense is a huge, huge part of baseball. To steal a quote from Bill James, much of what we call pitching is really defense. For all intents and purposes, the Chicago White Sox are world champions because they were a team of terrific defensive players who weren’t so awful at hitting or pitching that it would offset the strength of the team.
Clearly, if you’ve been reading our posts for the past few years, you’ve seen a change in the way we evaluate players. I stumped for Pokey Reese (well, a healthy one, anyways) for two years. The support of the signing of Jacque Jones is largely based on his defensive abilities and the effect he would have on the team’s pitching staff. However, it seems to me that the importance of defense is still underestimated by most fans. In fact, while I think our readers represent the upper tier of intelligent fans, I’d say that I would expect that most of you underestimate the importance of defense as well. We see this manifest a lot in the comments, when people suggest doing whatever it takes to bring in “The Big Bat”, including terrible ideas like shifting Richie Sexson to left field.
I’ve been trying to think of a good way to explain just how important defense on a team level can be in a way that would make sense and still be understandable. While there’s some good defensive work being done, most of it deals with mathmatical theory of regression analysis and other non-interesting reading material that I’ve slagged through. But, tonight, Chris Dial introduced his “method” of evaluating defense over at Baseball Think Factory. It’s not that tough a read, and it makes a lot of sense, especially if you’re familiar with some of the previous work that’s been done in this field. Now, there’s still enough problems with individual defensive stats that I’m not linking to this to back up any claims about a specific player, and I’m not saying that his numbers are the answer. I haven’t even given them more than a cursory glance. However, there was one table that jumped off the page at me that I’d like to share, and hope its importance sets in.
Position AvgZROps Runs/play Runs/Season AvgZR* Runs/Season Perfect Average 1B 281 .798 224.24 .870 195.09 2B 507 .754 382.28 .822 314.23 3B 430 .800 344.00 .783 269.35 SS 532 .753 400.60 .835 334.50 LF 348 .831 289.19 .861 248.99 CF 462 .842 389.00 .888 345.44 RF 365 .843 307.70 .873 268.61
Essentially, what this table tells us is how many runs an average player at each position saves over the course of the season. The baseline it’s compared to is zero, so don’t freak out because the numbers are huge. Essentially, what this is saying is that if you played a season with just 8 fielders and left everyone in their normal spot but eliminted the shortstop, you’d give up an extra 335 runs. If you punted the left fielder, you’d “only” lose 249 runs.
The difference between the positions should jump out at you. Center Field is the most important defensive position in baseball. It is way, way more important than right or left field. Think of it this way; an average center fielder will have the opportunity to save his team 70 more runs than his average right field teammate. Holy crap. 70 runs!
Defense isn’t something to be looked at as a minor factor in player analysis. We certainly haven’t discovered the key to perfectly evaluating the abilities of each player, but we should all be past the point of thinking that the vast majority of a player’s value is tied to what he produces with his bat. What he can do with his glove is far from insignificant, and needs to be considered.
In other words, just say no to Richie Sexson, left fielder.