Why Defense in Baseball Might Be Overrated

I say “might” because a lot of the people behind stats like UZR and FRAA and whatnot are very good at math and have put far more thought into this than I did driving to work this morning. Defense is a hot topic, and quite a few smart GMs (including Theo Epstein) have made defense a point of emphasis this year in their player acquisitions. This does not seem to be working. Seattle has basically been destroyed by focusing on defense to the detriment of offense. I’ve always been offensively-minded and I enjoy watching players like Adam Dunn and Russell Branyan, which is the mindset that these GMs were trying to cash in on, I suppose. That said, it seems to me that there is a good argument to be made that defense really is far less important than offense. There may be obvious holes in a few of these points (and feel free to point them out), but they seem to make sense to me.

1. The Zero Bound

You cannot hold a team to fewer than 0 runs. Think about a team made up of average pitchers, 5 Ozzie Smiths (assuming that Ozzie would be brilliant defensively at every position. And let’s leave catcher out of this for now.) and 4 average defenders. Say Ozzie plays 3rd, SS, 2b, CF, and RF, and Mr. Average plays 1st, LF, Catcher, and DH (say we’re in the AL). Already this is a brilliant defensive team. Ozzie in center will cover for most of the deficiencies of the LF, and 1B just isn’t that important a position to defend. Maybe this team gives up 2 runs a game where your normal defensive team gives up 3. Maybe a bit better than that, and maybe a bit worse. Now add another Ozzie. Put him in LF.

How much better did you make the team? The CF Ozzie was already helping Mr. Average LF a lot. Most of the field was covered by brilliant defenders. Most bloop hits were caught. Most plays deep in the hole were being made. Now add another Ozzie at 1st base. How this arguably helps even less. On defense, I would argue that except for catcher each additional investment you make helps you less and less. You are in a situation where you are realizing diminishing returns.

Now take a team of 5 Albert Pujols and 4 average batters. So far this year Albert has been worth about .456 runs per game better than a replacement level player. Average does not equal replacement level, but let’s assume that the replacement level 1st baseman (which is Albert’s baseline when calculating his VORP) is about the same as the average player in general. This may not be true, but let’s go with it. If we sub in another Albert for one of the average batters, we add another .456 runs per game. The Alberts do not cannibalize each other. In fact, by creating fewer outs they may actually help each other slightly. In short, adding offense does not have the same problem of diminishing returns as adding defense. You get more bang for your buck.

2. Balls in Play.

Defense is only effective on balls in play. Over the course of a game of baseball it is entirely possible that very few balls will actually enter a defensible part of the field. There will be home runs, walks, strike-outs, hit batsmen, and the occasional balk. In any given game the defense is probably involved in about half of all plays in any serious way. I think there have even been a few games in history where the only plays in the field were taken by the first baseman, unassisted.

3. Even when the ball is in play, most plays are routine.

Lazy flyballs are easy for almost everyone, and make up a large percentage of flyballs. Sharp line drives are usually hits, and are not catchable by almost anyone. Many grounders are soft, and right at players. Sometimes players his harmless pop flies.

4. Not every ballpark is conducive to great defense.

If you play in Fenway, there is no point in paying your LF for his defense. If you pay your LF for his defense and then play a road game in Fenway, you are at a disadvantage. Albert Pujols’ bat plays anywhere.

5. Defensive metrics are still more of an art than a science.

In short, even though great defense will only have an impact on a small number of plays per game, we’re still not that good at measuring that impact. We’re better than we used to be, and at least we understand the concept that being able to get to a ball and possibly committing an error is better (or at least about the same) as not being able to get to a ball and allowing a “hit”. But we still don’t have that one good defensive number.

I think this is right. I think offense is far and away the more valuable commodity and that a smart GM will wedge good hitters into whatever position he can if their bat is good enough. I think the focus on defense is especially ill-conceived for a big money team like the Red Sox who should be spending their money on guys who can hit. And I think Seattle might be bad for a long time.