Through my experience watching NPB, I've shown plenty of angst when it comes to the lack of quality defensive metrics beyond the limited RF/G and the outdated fielding percentage. Through Jim Allen's reports, we do know that NPB teams receive individual UZRs (Ultimate Zone Rating) which are currently the best way to evaluate the defensive performance of a given player, but these ratings are not released to the public, so we're only given a few crumbs beyond our eye test of a given player's defensive ability.
We can, however, find ways to analyze each team thanks to a metric known as Defensive Efficiency (DER) which measures the percentage of balls in play which end up being converted into outs by a team's fielders. It's a simple measurement that gives a basic understanding of a team's overall defensive performance over a given season.
I urge you to check out Baseball Prospectus' breakdown of Defensive Efficiency and what's usually a good DER rating, as well as an explanation on the DER equation. The only negative caveat involving Defensive Efficiency is that it doesn't exactly separate the effectiveness of pitching from fielding.
Here are the rankings. Please note that with the exception of the Marines, these numbers for all games through July 11th.
1. Fukuoka SoftBank Hawks .740
2. Hokkaido Nippon-Ham Fighters .732
3. Chunichi Dragons .726
4. Hiroshima Carp .720
5. Yokohama DeNA BayStars .716
6. Saitama Seibu Lions .715
7. Chiba Lotte Marines .714 (Through July 18th)
7. Hanshin Tigers .714
9. Yomiuri Giants .713
10. Tohoku Rakuten Golden Eagles .711
11. Orix Buffaloes .709
12. Tokyo Yakult Swallows .704
Note: While this information may be public for the Japanese media and others, we calculated this data by hand.
I'll start with the top of the rankings, and it's clear that the Hawks have earned their reputation as a tremendous defensive ball club and when putting them up against the current defensive efficiency standings of MLB, only the Chicago Cubs can best that mark with a current rating of .744.
There are many reasons why the Hawks have such a high rating. First of all, the Hawks pitchers lead the Pacific League in strikeouts so that limits the amount of balls that end up being in play, as opposed to a team like Chiba who's pitchers only strike out 5.8 per 9 innings. It seems like the only way to score against the Hawks is through the longball which is the only negative category that the Hawks lead the Pacific League in, mostly due to their ballpark bringing in their fences.
This rating reflects greatly on the Hawks' defense up the middle with Kenta Imamiya and Yuichi Honda, who are below average at the plate, but more than make up for it with their gloves. It must be great to be a Hawks pitcher, when you have such a defensive juggernaut playing behind you and will swallow up every batter that the pitching doesn't already manage to put away at the plate, and it's no shocker that the Hawks lead all of NPB in run prevention, as they only give up 3.16 runs per game.
Their main competing rivals in the Pacific League are second on this list and their overall run prevention is also on the tail of the Hawks at 3.29 runs per game. It's the overall run prevention that makes the difference for the Fighters who have so far improved upon their mark from last year which ended the year at 4.06 runs per game which was second to last in the PL last season. This, combined with the improved hitting of the Fighters has seen the gap between them and Hawks decrease dramatically and might actually give the Fighters an outside shot of catching Fukuoka.
There's a large logjam in the middle of the rankings, but what's interesting is that the Lions are considered average in terms of defensive efficiency. So much has been pointed out by other pundits that the Lions are an awful defensive team, and that's usually brought up because the Lions lead the Pacific League in errors. The errors are quite deceiving because the Lions allow the least amount of home runs in the Pacific League due to their spacious pitcher's park, while also posting the second worst team strikeout rate in the Pacific League.
To sum up this all up, the Lions defense sees the most amount of balls in play and therefore, a higher error count is expected. The blame for the Lions heightened runs allowed should instead be charged at the Lions pitching staff which give up the second-worst walk rate in the Pacific League with 3.7, with a tally like that, there's little room for error if the pitching staff struggles to strike batters out. The Lions are by no means, a good defensive team, but the errors are not the reason why the Lions have struggled to keep pace in the Pacific League race.
One last observation involves the team at the very bottom of the rankings and that's the Swallows. One year after the Swallows completed an amazing year that ended with a Central League title and a loss in the Japan Series to the Hawks, the Swallows have seen everything blow up in their collective faces. The Swallows have seen their impressive run prevention rate of 3.62 runs per game, jump to a current rate of 4.98, almost a run and a half jump from their magical season.
The Swallows haven't changed all that much on the mound, their strikeout rate is once again the worst in the Central League and their walk rate has hovered around the middle of the CL. These two things have been constants in these last two years and they are on pace to blow out of the water the amount of home runs given up in 2015 (112), as they are already at 88.
Ironically, the Swallows have actually seen their runs per game on the hitting side of things, actually go up from 2015, thanks to the efforts of a healthy Wladimir "Coco" Balentien. Instead, it has been the defense that has let them down with their pitching only giving up more home runs from the year before, it's just that this time, their defense behind them has failed to pick them up. And unfortunately for the Swallows, the teams that they are competing against for the third spot, are all average or better (with the exception of the Tigers) when it comes to defensive efficiency. Maybe next year, Tetsuto Yamada.
Let me know in the comments about what your reactions are to these rankings, we will be updating them at the end of season and I'll be talking about them more during our next podcast recording this week.
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