Sunday, March 3, 2013

 

By Gregory Bird, AngelsWin.com Columnist  -- 

Welcome to the new Inside The Numbers Feature. I’m Greg and I’ll be taking over this AngelsWin.com feature for the 2013 season. I hope to provide the same high quality analysis that AngelsWin.com is known for. My articles will be focused on the current Angels roster through the lens of sabermetrics. I also hope to give insight into how the Angels’ front office might be thinking when they make their decisions. I’m sorry, up front, that I may sound like a JeDi apologist (to be fair I really like his moves so far.) But what I really want to do is to dig a little deeper and understand better the game and team we all love. I don’t claim to be an expert but I do want to spark intelligent, thoughtful conversation based on the facts of the game.


So, why did JeDi let Torii go and sign Hamilton to a 5 year deal? This question has been kicked around this offseason. It is a fair question. Much of the analysis I’ve read says that Josh isn’t really an upgrade over Torii and that the only possible reason could be age. The articles tend to include, as support, the sabermetric stat of WAR (Wins Above Replacement.) They’ll say, “Well Hunter produced a 5.3 WAR in 2012 while Hamilton only produced a 4.4 WAR (according to FanGraphs.)” This means that at best they were equal but that most likely Josh won’t be as good for the Halos in 2013 as Torii was in 2012.

Don’t get me wrong here, WAR is an excellent stat and very useful, BUT it isn’t the end all and be all of sabermetrics. We cannot reduce performance to one number. One reason is our current lack of understanding of defensive metrics, a key component. WAR seems best used to help start an intelligent conversation, not to end one. 

WAR is often misunderstood. It is a comprehensive counting stat that combines the value of: a player’s defense (using either UZR/150 or Defensive Runs Saved,) a player’s bases running, and a player’s hitting. Their performance is then adjusted for their fielding position and finally distilled to how many wins they added to their team. The generally accepted formula is 10 runs equals approximately 1 win.

The problem with comparing Hamilton and Hunter’s WAR in 2012 lies in the defensive positions they played throughout the year. Hunter played 134 games in Right Field, an easier defensive position, where he excelled in saving 13 runs according to UZR/150. Hamilton played 95 games in Center Field and cost his team -26.3 runs according to UZR/150. He also played 86 games in Left and Right Field combined where he basically broke even with -0.1 UZR/150. 

Defensive stats are the least accurate and understood at this time and are best looked at over three seasons to improve accuracy. Over the past three years Hamilton has a positive 8.5 UZR/150 in Left Field and a positive 6 UZR/150 in Right Field. Additionally, Torii’s last year in Center Field was less than stellar as he posted a -6.4 UZR/150 in 98 games in 2010. So, for the purpose of comparing these two players last year I propose it is best to leave defense out of it for now. I am going to just look at their offensive production. I assume Josh in Right Field is going to be almost as good as Hunter in Right, not absolutely but close enough.

Much of what I’m going to be talking about includes references to a baseball statistical field known as linear weights. No, this has nothing to do with chemistry nor how heavy something is. It is a system developed to replace the basic stats we’ve grown up using (BA, OBP, SLG, and OPS) with a set of statistics that better represent the value of each action on the diamond. Every possible action has a weight or approximate run value it adds to an inning. The idea was conceived by trusting if we accurately value each possible offensive event than we can get the correct value of an individual player’s offensive contributions.

You may wonder why linear weights are needed. The reason is really rather simple. In slugging percentage, a homerun is 4 times as valuable as a single. In on base percentage a walk is as valuable as a homerun. In batting average a single is the same as a triple and walks don’t matter. It has become obvious that none of this is true. 

Sabermetricians embarked to find out the actual value of each baseball event and found out some very interesting things. First, the value of events change slightly year to year based on the overall environment of the game. Second, there are some basic relationships that are fairly constant like: a HR adds about 1.4 runs to an inning, a single about .47 runs, an unintentional walk adds .32 runs, a strikeout subtracts -.29, a groundout subtracts -.27, a stolen base adds .25 runs, and a caught stealing subtracts -.50 runs. There are more events and numbers but this gives you an idea of how linear weights work and how differing events are relatively important to each other. 

My first comparison between Hunter and Hamilton has nothing to do with linear weights, it is simply who possess the most power? To determine this let’s look at a stat called ISO or isolated power. It is derived by simply subtracting batting average from slugging percentage. This removes singles and lets us know who is likely to produce more extra base hits. Hunter’s ISO last year was .139, the average for 2012 was .151. Hamilton’s ISO was .292. Hamilton was more than twice as likely last year to have his hit go for extra bases. This isn’t a big surprise but it is significant. Because of his power Josh is more of a run producer than Torii and this is my first reason to like this Hamilton guy.

Next let’s look at a stat called wOBA. Weighted On-Base Average (wOBA) is a good measure of a player's offensive value. Weighted On-Base Average attempts to package a player's entire offensive output into one statistic using a form of the run values in linear weights.  It takes these run values and converts them into a familiar usage to all baseball fans, that of OBP. When looking at wOBA values an average hitter is around 0.340 or so, a great hitter is 0.400 or higher, and a poor hitter would be under 0.300. 

Last year Hunter had a wOBA of .356. He was well above the league average of .315. Hamilton, in 2012, had a wOBA of .387. He was 72 points higher than the league and still considerably higher than Torii. Talking in terms of OBP a 31 point improvement is significant to a player or team. Josh was also only 13 points shy of hitting the threshold of having an all-time great year. He finished the season ranked 10th overall in terms of wOBA among qualifying hitters. But you may be asking but how much of this is related to his hitting in Arlington? Let’s dig some more.

How many more runs could Hamilton produce for us in 2013 than Hunter did in 2012? What about our park, it isn’t hitter friendly, how will Hamilton compare here? Here are two stats that will help us solve these problems. They are Weighted Runs Created (wRC) and Weighted Runs Created Plus (wRC+.) Weighted Runs Created is a counting stat based off of wOBA that gives us the raw number of runs a player ‘created’ in a season. Weighted Runs Created Plus measures a player against league average (100) and tells us how much better or worse they were in terms of percentages than the league. wRC+ is also league and park adjusted so we can compare players accurately apart from their seasons or environment. Remember wRC+ is a percentage comparison so a few points different can be significant unlike wRC and other counting stats (i.e. HR, RBIs, or even WAR.) 

Let’s dig into these numbers. Hunter created 86 runs in 2012 and Hamilton created 109 runs according to wRC. That means the 31 point difference in wOBA amounted to 23 more runs being created, a significant amount. If 10 runs equal a win then it is about 2.3 more wins in Hamilton’s offensive output than in Torii’s. 

But how did their parks affect them? In 2012, Torii posted a 130 wRC+; he was 30% better than the average major leaguer after adjusting for Angel Stadium and the AL. Josh posted a 140 wRC+; he was 40% better than the average major leaguer and was tied for 13th overall among qualified hitters. This means Josh was 10% better than Torii once we adjust for the parks they hit in. This isn’t a lot but once we start looking at elite hitters it very hard to find a 10% improvement over someone who is already very good. 

Why do I think JeDi choose this Hamilton guy over Torii? First, he is a more powerful hitter who can do more damage in the lineup. Second, he provides more offensive value than Torii did last year and still delivers top notch defense. Third, he’ll most likely create more runs for the team, even hitting in our park. Fourth, he is younger and while Torii is aging well nobody knows how his next two years will turn out. Look at the first year of Abreu as an Angel compared to his final two years. 

While it may or may not work out like JeDi envisions I think it is always wiser to let go of a player one year to early than one year too late. For this I think our GM made a difficult but smart decision. I think this Hamilton guy will be more valuable to us in 2013 than Torii was in 2012. That’s all I need to know to be happy with the decision.
Love to hear what you think!

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