2B and 3B

This afternoon, we touched on position adjustments and why they’re needed. In the case of positions such as 1B and SS, it doesn’t take a lot of explanation as to why there needs to be a bridge so that we’re not describing an average SS equally valuable to an average 1B. However, for a few other positions, the line is much less clear. The three positions where the respective defensive abilities is less clear are second base, third base, and center field.

In a lot of circles, you’ll hear defense described in two sections – “up the middle” and “the corners”. You’ll often hear the up the middle spots – C-SS-2B-CF – as being premium defensive positions, where teams will look for gloves first and bats second. The opposite is true in the corners – 1B-3B-LF-RF – where teams want offense and consider defensive value a bonus. By this definition, second base and center field are glove first positions, but it’s something of an afterthought at third base. If we bought into this notion, we’d believe that third baseman, as a group, are inferior defenders to second baseman and center fielders.

This notion is reinforced by the fact that third baseman are better hitters than second baseman. Major League 3B hit .266/.336/.436 last year, while Major League 2B hit .276/.338/.409. This has been a trend for a while, and since the statistical analysis revolution taught most of us to think in terms of player value in terms of above or below average in relation to the offensive average of that position, we’re used to drawing conclusions that worse hitting positions are better fielding positions. Since 2B hit worse, they field better. That’s the assumption. The problem, though, is that it lacks evidence. There is simply not a large fluctuation in defensive performance when a player moves between the two spots.

Take Akinori Iwamura, for example – he played a full season at 3B in 2007, posting a -2.6 UZR/150 at the hot corner. The Rays moved him to second base for 2008, and he posted a +0.6 UZR/150 at the keystone. He’s not the exception, but instead, performances like this are the rule. When a player moves to 2B from 3B, or vice versa, their defensive performance remains relatively stable. There’s just no data to support the idea that second base is a premium defensive position and third base is not.

While there are different skills necessary to succeed at each position (arm strength being more important at 3rd, range more important at second), the pool of players who can succeed at one is mostly made up of the same pool of players that can succeed at the other. This is because the population of both positions is made up almost exclusively of players who were deemed inadequate for shortstop. At one time, second baseman and third baseman were both called the same thing – bad defensive shortstops. From there, they were separated into 2B and 3B pools, but the evidence suggests that the crop of players who end up at 3B are better overall players than their 2B brethren. Why? I have a few theories, and we’ll get into those tomorrow.

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Dave is the Managing Editor of FanGraphs.

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Ryan Braun also made this pretty obvious with his move from 3B to LF netting a gain of some 30 or so runs.