There are a lot of misconceptions out there about what we mean when we say, for example, that the average NL team is currently eight wins weaker than the average AL team or that we think AAA has an EqA 12 points lower than the NL and 24 points lower than the AL.
What do we mean by League Quality?
Well this is actually a very complicated problem that involves - essentially - a four-moment curve-fitting exercise. Let's break it down a bit, starting with the simplest statistical facts.
Human Ability is Typically a Bell Curve
We know well that if you could somehow gather up everyone who has ever played baseball at a level beyond little league (seriously attempted to hone their skills), you would see a natural talent distribution emerge that resembles the natural talent distributions for everything we humans do, from problem solving skills (measured by IQ) to test taking performance (like the SATs) to maximum running speed to spelling skill. Gather enough humans in any kind of skill-related contest and a bell curve emerges. Baseball is no different.
But Any Baseball League - ANY League...not just MLB - Follows Different Rules
Bill James was almost right. He pointed out that major league baseball is played by the top one hundredth of a percent of the population of serious baseball players. If you take the overall serious ballplayer curve and chop off the top 0.0001 percent of its' bell-shaped area, you'll get a pyramidal distribution with a sharp cut-off required for entrance into the MLB sample and a long tail with exponential decay. This is further complicated, however, by a number of factors that James didn't quite get to in his (intentionally) simple explanation for why MLB stats aren't normally distributed. He wasn't trying for the precise definition. In reality, the left side of the MLB curve is influenced by ATTRITION. Because MLB teams do not precisely know who will succeed or fail at the highest level, and because players are human and their abilities change over time (or they lose interest in continuing with their careers, or they get injured, etc), the left side of that curve is no longer a peak with a sharp cut-off, Those weaker players that would dominate the distribution get shaved off and constantly repalced and the stronger players get more playing time. The result is a very different kind of gaussian curve called a Weibull distribution. The most common application of the Weibull curve is in failure analysis (take a product and torture test it repeatedly...it will usually fail at variable times with the probability of lasting X timesteps defined by a Weibull curve that tells you a lot about the quality of manufacturing of that product). But it also applies to a left-bounded talent curve where there is considerable exchange of talent at the left hand side.
ge player from the first is a minor star in the second! You could also have a league that is overall better without it necessarily meaning the star players from the weaker league will see much change in their performance from they cross over to the stronger one. The future of context adjustment of historical performance lies in curve fitting...I'm absolutely convinced of this. We need to make some estimate of where each league's talent distribution lies on the linear talent spectrum and then fit each league's curve shape to a standardized model. That's the only way to get a semi-realistic view of the game's history with league quality in mind.
WHen it comes to the NL and AL of today...we know that the NL is about eight games weaker than the AL in terms of a team of average players from each league (per 162 game schedule)...that's a good starting point for the linear adjustment. But we need to know something about the shapes of the leagues' Weibull curves for performance before we can estimate how Albert Pujols would do in the AL...or how Hiroki Kuroda would do over here, for that matter. My guess is that the AL's talent curve is both shifted right AND more efficient (taller with a skinnier right tail)...meaning that a star player from the NL shouldn't see much change coming over here (see Cabrera, Miguel), but that even an average NL player might well be an RLP in the AL (or at least considerably closer to RL).
I'd make some figures to illustrate my meaning here, but I've got a lot to do and no time to sit and draw curves in paint. :) You can do this yourself, though. Look at the shapes of Weibull curves in the figure above...now imagine choosing squatter curves or taller ones and shifting them left or right...draw some figures on a piece of paper to see how, say, the 25th percentile player from one curve might perform on another curve. Or the 95th. Or the 50th.
League quality is not linear...nothing in baseball is. We've got to get past thinking of league quality the way James did (he did this because he was trying to make a quick estimate...I don't fault him for that, but I do think he's going to turn out to be pretty darned far off in some cases). We need to start thinking of leagues more wholistically.
I hope this has given you all something to chew on in light of the recent debate about league quality.
My .02, FWIW,
SABR Matt
Great Stuff Matt.
Chopping the NL's extra 2 teams and ridding of the DH would probably cancel a lot of the AL-NL disparity.
Ultimately it comes down to whether or not a player is feasting on fringe players that won't exist in a superior league. The players that do feast on these players will likely suffer a much bigger decline than those that are more productive vs high/middle tier players.
...I would think it would be rare for a player who produces very well in the NL to be a player who only does so against inferior competition. I think a curve-fitting exercise will tell you just as much as looking at splits vs. good teams vs. bad teams would. But yes...the problem with the NL to AL players who flounder is that they ahve been feasting on guys who wouldn't be RLPs in the AL.
For example, you could take the #5, #10, #15 ... #50 hitters in the NL and AL, and gather their performances against pitchers with low ERA's.
There is some site that runs splits vs. pitchers with low and high ERA's, isn't there? ESPN used to run them against power and soft-tossing pitchers and, of course, vs. GB/FB pitchers. But I thought I saw someplace that had year-end splits against lo/mid/hi ERA, too...
James does this in the Goldmine. I was literally just reading about this in someone else's copy of the '08 edition. Beltre in particular was singled out on the Mariners for struggling against good pitchers and feasting on worse. Johjima actually did better against good pitchers and worse against the lousy ones.
Were remarking, at the time, that Johjima was an example of a Mariner who could hit pitchers' pitches, and Beltre being the opposite of that. Probably a few remember that discussion.
You know what, though, it's hard for me to visualize the NL being a league full of hitters --- > who go up there whaling away for cheap long balls off tater pitches.
Which is about 10 degrees off subject, but not 180 off.
Hiroyuki Nakajima appears as though he's about to be posted. Would the M's be interested? He's fairly reminiscent of Kazuo Matsui when he came over, except for a few important differences. Kaz Matsui hit more home runs, was smaller, generally stole more bases, walked less and struck out more. He was also very highly regarded at the time and ended up signing for 20 million over 3 years and mostly floundering in the Majors (He did have 2.25 good years). In this story, which makes it seem less that he's likely to be posted and more that he wants to be posted, it suggests that his posting cost would likely be fairly low. Assuming a lot of things: he gets posted, he can play a decent shortstop in the majors (Matsui couldn't despite gold glove reputation), he puts up Matsui-like numbers (low .700s OPS would be the most I would expect for this righty at Safeco), and that he would sign for 2-3 years at 2-3 mil per year. Would he be a player you could see the Mariners going for?
He does have a few things going for him, including an EYE ratio of better than .5 over each of the last 3 seasons and the fact that his name isn't J. Wilson. In a year where there's no likely free agent shortstops and we're still at least a year and a half from the Nick Franklin era, I think he could work, get rid of one of the black holes in the lineup.
He's not GREAT, by any means...but he's probabiy about as useful as the much ballyhoued J.J. Hardy in terms of overall value (remember how much the blogosphere wanted us to give up to get Hardy?)
He plays a roughly average SS, I'm told, and he's got enough of an eye and enough contact skill that I have to believe he could at least manage a .280/.330/.400 kind of line in the bigs. He reminds me a little of Akinori Iwamura except we'd be getting one extra peak season (he's coming over at 27, not 28).
In a vacuum I'm interested in replacing our ridiculously pitiful SS combo with even a league-average SS. Nakajima is a decent 2B/SS and we are very familiar with the trials of bringing Japanese players over, so landing here should be simpler for him and for us.
In practice, since it's been fairly well shown that we cannot ever trade a Japanese player once they are on our team or reduce their pay in any way and must hope for a face-saving retirement back to Japan rather than dismiss any of them...
I'm leery of adding a RH hitter who relies on HRs in Japan that he won't get here, and that we can never EVER replace regardless of his performance.
There is no guarantee that Nick Franklin is gonna be the SS we really need him to be, but adding Nakajima makes Franklin instantly the greatest trade bait we are willing to dangle. His position would be blocked off for the next half-decade with us, at least.
If we're okay with that, and we don't think Nakajima is gonna faceplant power-wise like Kazuo Matsui did, then fine, I can be interested in using him to upgrade our SS position. Remember, though, that Kaz hit 23, 24, 36 and 33 HRs in his last 4 seasons in Japan, with very good batting averages those years (.305 to .332).
He never cleared 10 HRs in the bigs in any season, which made his career average of under .270 the best thing he had going for him. Nakajima has 21, 22 and 20 HRs the last 3 years, with a batting average between .309 and .331. The benefit with Nakajima would seem to be that he can take a walk - for a Japanese player anyway. He walks like Ichiro did in Japan, though he Ks a lot more.
Maybe he can be Tad Iguchi. Getting the 28-29 years of Tad Iguchi at SS (or 2B) added to his 30-32 years doesn't sound bad at all. Tad's power died at 32, never to be seen again.
Still, that's 4 years away for Nakajima. We just don't play in the ChiSox hitter-friendly park. It's a risk, especially since he'll be here until he retires from MLB.
~G
Good point, G...
Iwamura is a good comp, plus a little more D. I like Nakajima. Hes a probable 3 WAR~ish SS and thats a pretty big need for the Ms.
I think its more likely he gets posted next season though. Good target for us. K.Matsui was such a bust that I think Nakajima might come cheap.
Though the fact that Iwamura got 4.5 mill to post (well after Matsui flopped) is a little concerning considering there wasn't even the possibility of him playing short. It is interesting to note though, that neither Matsui or Iwamura struck out like they did in Japan, but both players did nearly maintain their walk rates.
I think Iwamura and Matsui K'ed less in the Majors because in Japan, they were good enough to be aggressive and open up their swings, but against big league pitching, they had to tone down their aggression to avoid looking foolish si they took out their pepper swings. That's part of the reason their power dropped and also why their K rate dropped. The same was true of Kenji Johjima.