Pittsburgh Turns the Power Out

The Pirates have already locked up their first non-losing season since 1992. Any day now, they’re going to win one more game and guarantee an actual winning season. This would probably be a bigger deal if the Pirates were worse. If it came down to the season’s last weekend, there would be a lot of chatter about the Pirates officially snapping a humiliating two-decade streak. Instead there isn’t any suspense, and observers are dreaming bigger. 90 wins. Division. World Series. Long-term sustainable success. It feels beneath this year’s Pirates to celebrate an 81st or 82nd win, and indeed, these Pirates have little in common with a lot of editions of the Pirates from the recent past.

But, 20 years of losing. Of losing all the damned time. One shouldn’t lose sight of how incredible that is, and one shouldn’t deny that even a little winning’s a relief. How have the Pirates, at last, managed to turn things around? Don’t go pointing fingers at the run production — the Pirates rank tenth in the league in runs per game. The story, as should be familiar by now, is run prevention. In runs allowed per game, the Pirates are second, behind only the Braves. Just three years ago, they were dead last. It’s interesting that the Pirates haven’t been allowing many runs, and it’s interesting how they’ve managed to accomplish that.

If you’d like, you could just look at their low team BABIP, or their high team left-on-base rate. The Pirates are in the middle of the pack in strikeouts, and they’re worse than that in walks. They don’t seem like a tremendous run-prevention unit, but there’s one thing they’ve been doing in particular that’s allowed them to keep runs off the board. A good way to score runs is by clubbing extra-base hits. So the Pirates have decided to not let people do that.

Going through the history, you can see some trends in league-wide isolated slugging. Baseball entered a new era in 1994. That year, the major-league isolated slugging jumped to .155, and it’s hovered more or less around there since. I’m not going to name this era, but let’s think of it as an era, in which this is the 20th year. All right. I’ll begin by pointing out that this year’s Pirates, so far, have allowed a .103 isolated slugging. That’s an excellent mark; it’s the best mark in baseball. And we can go beyond just looking at 2013.

Let’s look at the whole 20-year window of ISO elevation. From between 1994-2013, here are the top ten 13 lowest ISOs allowed:

  • .103, 2013 Pirates
  • .112, 1997 Braves
  • .113, 1998 Braves
  • .114, 1994 Braves
  • .114, 2011 Giants
  • .116, 1996 Dodgers
  • .120, 1995 Braves
  • .120, 2003 Dodgers
  • .121, 1996 Marlins
  • .121, 2011 Phillies
  • .121, 2013 Cardinals
  • .121, 2011 Braves
  • .121, 2002 Giants

This year’s Pirates have allowed the least power in baseball over a two-decade window. Their ISO against is 38 points better than it was last year, 41 points better than it was the year before that, and 64 points better than it was the year before that. No team in baseball this year has allowed fewer home runs. No team in baseball this year has allowed fewer combined doubles and triples. So, when runners have managed to reach against the Pirates, they’ve been extra difficult to drive home. This is helping to inflate the Pirates’ rate of stranded runners. Their average hit allowed has been less valuable than the league’s average hit allowed.

So, we know what the Pirates have done through the first five months, at least in this regard. The next step: how do we explain it? Why is the Pirates’ ISO allowed so low? You can probably do all this yourself, but the way I see it, there are four points. Four pretty obvious points, but how embarrassing would it be if I didn’t acknowledge the obvious?


Every pitching staff is going to allow balls in play. Lots of them! Even a pitching staff composed exclusively of Craig Kimbrels would allow lots of balls in play. Balls hit in the air are more likely to go for extra bases than balls hit on the ground. Grounders are outs and singles. Flies and liners are outs and singles and doubles and triples and dingers. The Pirates have allowed plenty of balls to be hit in the air, but on a rate basis, they’ve been terrific at keeping their infielders occupied.

We have batted-ball data going back to 2002. Since 2002, this year’s Pirates have the highest team groundball rate, at 52.8%. In second we find the 2005 Cardinals, back by more than two percentage points. It’s not quite fair to say the Pirates are extreme like this, but it’s all about little differences, and in this way the Pirates reduce opportunities for extra-base hits. The grounder thing might well be deliberate. From a post that Eno just published:

Cole agreed. “That’s all they preach is ground balls,” he said. “Ground balls and fastball efficiency, really, trying to create plane with the fastball. That creates sustainability. When you come up with a faster breaking ball, that’s good. But in the long run, for the guys who pitch for a long time, it boils down to fastball command.”

This year, facing groundball pitchers, batters have posted a collective .126 ISO. Facing fly ball pitchers, they’ve posted a collective .156 ISO. Grounders come with their own set of potential problems, but keeping the ball on the ground more often should yield extra-base hits less often.


As noted earlier, the Pirates aren’t just first in fewest homers allowed — they’re also first in fewest doubles/triples allowed. It stands to reason this has at least a little something to do with the outfield defense, and Pittsburgh’s outfield defense has frequently involved both Starling Marte and Andrew McCutchen. By the range-rating component of UZR, the Pirates rank eight-best in baseball. They rank similarly in Defensive Runs Saved. They haven’t featured the league’s top outfield defense, and right now Marte is sidelined by an injury, but the gloves have helped more than they’ve hurt, and it’s possible they’ve been particularly good at preventing extra-base hits, and a little less good at preventing singles. In this post, we don’t really care about singles.


Now for the stuff that has less to do with the Pirates themselves. Stuff that’s just explanatory. The fact of the matter is that the Pirates call home, somewhat quietly, a pitcher-friendly environment. This year, the Pirates have allowed 29 dingers at home, and 60 dingers on the road. They’ve allowed a .077 ISO at home, and a .132 ISO on the road. Since PNC opened, it’s yielded home runs in 2.2% of all plate appearances. In Pirates road games, there have been home runs in 2.7% of all plate appearances, meaning PNC has a simple homer factor of 0.82. In the past, Safeco didn’t allow many dingers, but they moved the fences in. In the past, Petco didn’t allow many dingers, but they also moved the fences in. It’s possible that PNC is now the most homer-suppressing environment in the league. We can’t say for sure, and AT&T gives it a run for its money, but most simply, homers are tough to hit in Pittsburgh, and the park doesn’t inflate doubles and triples to offset it. PNC is tough on power, and PNC is where the Pirates play half of their games.

So, this is another reason the Pirates have allowed a low ISO. They’ve allowed a less low park-adjusted ISO. PNC should probably get more attention for being what it is, and maybe it will, now, with the Pirates done sucking, and with a couple other extreme environments becoming less extreme.


Sorry. I know this is dull and cliche. I know you’d die happy if you never had to hear “sample size” again, and I won’t spend long on this section. Nobody likes to read it, and it’s not even particularly fun to acknowledge it. But, it warrants acknowledgment. In a statistical category, this year’s Pirates stand out, within a window spanning 20 years. That makes their ISO allowed relatively extreme, and extreme performances have to be regressed to non-extreme performances. Presumably, the Pirates’ ISO allowed is low in part for reasons unrepeatable. Skill + luck, basically. It’s always skill + luck. It’s always skill + luck. In everything, everywhere. This omnipresence makes the notion uninteresting, but it also makes it critical. So.

Within an era of elevated isolated slugging percentages, the 2013 Pittsburgh Pirates have allowed the lowest isolated slugging percentage. Some of this is probably just luck, and some of this has to do with the power-suppressing home environment, but a lot still has to do with the Pirates, so it’s not like this can’t be considered a team strength. Against the Pirates, it’s more difficult to hit the ball out; against the Pirates, it’s more difficult to drive runners home. There are less subtle ways to prevent runs and win ballgames, but all anyone cares about is that the Pirates are preventing runs and winning ballgames. Given the ends, they’ll take the means.

Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

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10 years ago

Interesting. How does their isolated slugging compare to teams from the 1970s or 1980s?