Friday, January 04, 2008
UZR positional adjustments
MGL was nice enough to send me the 2007 UZR. I can’t release the details, but I can do what I do. As I like to do, I’ll compare the UZR by positions, for the guys who play multiple positions.
For the OF, this is no sweat, since the skill set involved in all three positions is very similar. From 2003-07 (that’s 5 years of data), I’ve got 7523 matching games for LF/RF. For example, take Geoff Jenkins: he has 351 games in LF and 280 in RF. I count that as 280 “matching games” (the minimum of the two).
Games, by the way, is basically based on number of flyballs hit to the player divided by the league average number per game.
Do this for the 300 players that played both positions. Add it up, and you have 7523 games. The UZR for those guys, while in LF, was +0.7 runs. And those exact same players, while in RF, was +0.1 runs. That is, the comparison points in LF and RF are different for the same guys. In order for you to standout in LF more, you have to be compared against inferior players. And that’s what we have here: the average fielding LF is 0.6 runs worse than the average fielding RF. And that’s just in range. (If you include the arm, we’re probably talking about a 2 run gap between LF and RF.)
When we repeat this for LF/CF, we get 5863 games. Those players are +4.4 in LF and -5.9 in CF, per 162 games. That’s a 10.3 run gap. For RF/CF (4930 games): +2.1 in RF and -9.9 in CF. That’s a 12 run gap. We have to make one adjustment though. CF get about 30-35% more BIP than in the corners. Scaling the CF opportunitues down to the number of LF/RF opportunities, we get:
LF/CF: +4.4 / -4.4
RF/CF: +2.1 / -7.4
Now, the LF/CF gap is 8.8 runs, while it’s 9.5 runs for RF/CF. From this standpoint, the RF is 0.7 runs worse than the LF.
Overall, we can say that the avg LF = avg RF which is 9 runs worse than the avg CF (when scaled to the number of opportunities of LF/RF).
I’ll be back later for the other positions…
When we compare SS to 2B, there’s a 4.3-run higher baseline at SS. No surprise there.
But, when we compare the SS to 3B, there’s only a 2.8-run higher baseline at SS. So, from this standpoint, the average SS is closer to the average 3B than to 2B. A bit of a surprise.
However, the 3B to 2B comparison shows a 3.9-run higher baseline at 2B than 3B. So, we have an inconsistency here, much more blatant than the one in the OF.
What if we looked at all players who played all 3 positions? Nick Punto and Craig Counsell lead the way here, for a total of 2020 games with 115 infielders. Those guys are -1.9 at 2B, -1.4 at 3B, -3.4 at SS. In this case, we see just a 2-run gap between 2B/3B and SS. 2B and 3B come in very close to each other.
If I put the two together, I’ll focus on the 2.8 and 4.3 run gap between SS and the other two positions (average of 4 runs).
The 2B and 3B can be interpreted in many ways, all of which to say that they are probably equals. In one comparison point, the 3B is closer to SS than 2B (by 1.5 runs). In a second comparison point, the 2B is way ahead of the 3B (by 3.9 runs). And in the third comparison point, 2B is a bit ahead of 3B (by 0.5 runs). Overall, you might think of the average 2B to be 1 run ahead of 3B. Might as well call them even.
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When I do the triple-position in the OF (3067 games), I get: 2.7 in LF, -8.6 in CF, and +3.9 in RF.
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These numbers continue to confirm my rule of thumb spectrum:
IF: SS 5 runs ahead of 2B/3B
OF: CF 10 runs ahead of LF/RF
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Next up, 1B…