Saturday, August 9, 2008

Junior Rejuvenated?

After Ken Griffey Jr. was traded last week, I had a discussion with someone about the impact of the deal on the White Sox. My point (as stated in the post about the trade) was that Junior's bat is still pretty good, but it's no longer great and that his horrible defense (in RF no less) counteracts it, and then some. The counter-argument was that Griffey is going to a contending club, which should "energize" and "rejuvenate" him, and "give him back his fire". And so on, and so forth. There was more to it than that, but the main points were (1) Intangibles make players play better (and also the players around them) vs. (2) Intangibles can allow a player to play to their fullest potential, but Junior's potential isn't that high anymore and so even if he has been "rejuvenated", he still won't help Chicago that much (if at all).

This raises a simple question: does going from "playing out the string" to being in a pennant race in the middle of a season cause players to step up there game? I decided to find out. To do that, I looked at the trades from June, July, and August from 2001 to 2007 in which a player went from a club out of contention to one that was fighting for a play-off spot. Now, it was a little complicated to look at the records (and standings) of the teams at the time of the trade, so I estimated based on the final standings. Generally speaking, if a team was within a few games of a division title (or the wild card in many cases) I counted them as a contender. If a team ended the year 64-98, then I assumed a player wouldn't be giving it his all in the dog days of the summer. (Actually I don't really think that - I think a guy will rarely make it to the majors if he does that kind of thing to a significant degree - but for the purposes of this exercise, it's what I went with.) I only counted players with at least 75 at bats or 50 innings pitched both before and after the trade to try to minimize the small sample size issues a little. Since there are other factors affecting performance, like the change in leagues or ballparks, I used OPS+ and ERA+ as my comparison stats since they account for such things. Also, since both are on the same scale, I can combine the pitchers and the hitters together.

There were 54 cases to look at, with three players being traded multiple times (Kenny Lofton and Carl Everett twice each (with the White Sox acquiring Everett both times in consecutive years), and former O's favorite Jeff Conine three times). I looked at the actual change in OPS+ or ERA+ (going from 80 to 100 is a +20) as well as the percentage change (going from 80 to 100 is a +25%). So, the results?

The average OPS+/ERA+ change ended up being +0.8; a player, an average, would go from an OPS+ of, say, 113 to 113.8. In other words, it was pretty much exactly the same. The average percentage change was +4.8. How about when taking out the outliers (those cases more than two standard deviations from the mean like Julio Lugo going from a 124 to a 41 OPS+ (-83) or Woody Williams going from an 81 to a 189 ERA+ (+108))? Well then the average change goes all the way up +1.8, and the average percentage change actually goes down to +2. If there is a "contention factor", it is clearly not very significant. I would also like to mention that I originally stopped at trades back to 2002. At that point, the average change was negative at -3 (which means players actually got a little worse when the pressure was on) and the average percentage change was 0. I'm not going to discount 2001, but I think that goes to show that using a one point increase in OPS+ from 01-07 to support the intangibles theory isn't sound.

Not one to stop right away having seen that my argument was supported, I broke the cases down into groups by their OPS+/ERA+ before the trade. Maybe OK hitters (Junior had an OPS+ of 103) go up significantly more than others, or whatever. Here's a poorly constructed table showing the results. Notice something? That would be regression to the mean. Every group moved in the direction (and partially) by the amount that would be expected. The bad generally got better (except for Rey Sanchez, who started at an OPS+ of 76 and still managed to drop 45 points) and the good got worse (though Mark Teixeira did what he could to help Atlanta get to the postseason last year).

When the groups were split between pitchers and hitters, the former were the ones that actually improved (by 9 points, on average) while the hitters did worse (by about 3 points). They do say that when a pitcher faces a hitter for the first time, it's the pitcher that has the advantage - that may be what is going on here as in most cases the pitchers switched leagues and would thus be more likely to face batters unfamiliar with them. The batters switched leagues slightly less often.

My favorite part was that the changes actually fit a normal distribution (mostly).That doesn't necessarily mean that they're random, but I think it makes it difficult to support the notion that getting traded to a contender causes a player to play better. Sample size caveats and all that not withstanding, I think I've made my point. More could be done with this, such as looking at players going the other direction (from good to bad teams) or traded players in general. I made my argument here with numbers though,and USSMariner made a similar argument here with words - that's good enough for me.

Does all that mean that Ken Griffey Jr. won't play any better in Chicago? Of course not. He was actually a bit unlucky on balls in play earlier this season, and so his offensive stats should improve some. Then again, he is going to the harder league. Frankly, I don't really care about his bat that much (it's not outstanding and not horrible) - it's his atrocious defense (especially in center) that is going to make it unlikely for him to really improve the team. Now, one could make the argument that I didn't look at defense here, but it seems silly to me that a player would play better on defense, but not when hitting or pitching. It's a little harder to find a defensive metric to work with, so I'm going to pass on looking at that myself. Maybe instead I'll do the 1,526,039th study showing that "clutch" doesn't really exist. Or go look for some more living room furniture on craigslist - you know, something that might actually benefit someone.

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