You Say You Want A Revolution

The fly-ball revolution is in full swing. The number of hits classed as fly-balls (a hit with a launch angle between 10-25 degrees) is on an upward trend, as is the average launch angle of all hits in the league. Home run totals are going through the roof and in an attempt to understand why Ben Lindbergh and Michael Lichtman concluded that the balls being used in games at the elite level are probably juiced in some way. Individual players have seen a massive increase in their run production by adjusting their approach to modify their launch angle. Most notably, Francisco Lindor hit more homers last time out than he had in the previous two years combined, by increasing his average launch angle from 7.7 to 13.7 degrees – just look at the perfect arc on this monster smash off Chris Devenski:

So whilst it is not a huge surprise that teams have been getting in on the action, there are some teams who have not. The Mets and Twins, with relatively hitter-friendly ball parks, are second and third on the list respectively, but Athletics, Royals and Padres, who make up the rest of the top five all play in home run-suppressing home parks, so it is a bit more surprising to see them with such high fly-ball percentages.

gb to fb

Of those teams in the top five GB/FB rate from last year, only the Twins had a winning season, so in basic terms you might say that the strategy hasn’t been great for them, but that’s not necessarily a fair way to evaluate the strategy.

The Royals, who objectively speaking have become worse in the period since their back-to-back World Series trips in 2014-15, are an interesting example. They went from being a 95 win team to being an 80 win team in just two seasons, but most visibly because of their pitching and defence. In 2014-15 they allowed 1265 runs. In the two years since then, they’ve allowed 1503, representing an 18% increase.

The Royals appear to have consciously changed their run-scoring approach in this period as well. The back-to-back World Series-reaching Royals were a small ball team built with speed and steals. In 2014 they stole 153 bases, the highest total in MLB, but last season they stole just 91, tied with the Marlins for tenth most. What they have been doing since then to get their runs instead is to hit for more power, with their ISO jumping 53 points from .113 to .156 from 2014 to 2017. They seem to have achieved this increase with a proclivity to hit the ball in the air.

Graph showing Royals FB% relative to league average.
Graph showing Royals FB% relative to league average.

Not surprisingly, their increased tendency to hit fly balls has brought with it a whopping increase in home runs. In 2014-15 they hit 234 homers, but in 2016-17 they hit 340, which is an increase of 45%! Their Slugging Percentage trended up considerably too, from .376 in 2014 to .420 in 2017. So in spite of their pitching and defence deteriorating, their increases in SLG, HR’s and ISO should have upped their game in terms of scoring runs, right?

Wrong. In those four seasons, the Royals’ run production has basically stayed the same, 2014-15 yielding 1375 runs, and 2016-17 yielding 1377, just two more! Unfortunately, it seems the home runs could do little to help them score runs, as with the third-lowest OBP in the majors last year they couldn’t men on base to be driven home. So why have the Royals changed the way they score runs? Why have they so wholeheartedly committed themselves to the fly ball revolution?

It could be the herd mentality – the idea that if everyone else is doing it, it must be the right thing to do, and wanting to get the best out of players  But that doesn’t really tally with the Royals, who had seen the benefits of their approach bear fruit in reaching consecutive World Series. It could be that they came to the realisation that home runs are a lot cheaper to roster than batting average, OBP and steals, and they were faced with the challenge of replacing ageing and/or expensive talent with more affordable options. It could be that they wanted to get the best out of guys like Mike Moustakas and Brandon Moss, both of whom saw increased home run output through greater average launch angle and exit velocity. Most probably it is a combination of all three factors, but clearly it hasn’t worked for them unless you argue that they would have been even worse off relative to 2014-15 if they hadn’t embraced the change.

What about at the teams who have been slower at boarding the runaway fly-ball train?The San Francisco Giants were one of those teams with a lower OBP than the Royals, and they managed a paltry 128 home runs in 2017 – not much over half the league average of 203. Well-known for having the most home run-suppressing run-scoring environment, the Giants recruitment this offseason hints at them wanting to address their GB/FB rate in the coming year and also hoping to score more home runs.

In replacing left-handed hitter Denard Span, who struggled to go long with the Giants mammoth right field, and Christian Arroyo, who ranked eighth-lowest in fly-ball rate last season with right-handed former all-stars Andrew McCutchen and Evan Longoria, they’ve beefed up their home run potential considerably. McCutchen hit 28 homers last year, but only 9 were hit at PNC Park. The home run park factors in AT&T Park’s left field are actually more favourable to right-handed hitters than those at PNC Park, so the double below, off the left field wall at PNC Park, is a home run in San Francisco.


What is clear is that it is all a question of finding the right balance for each team’s unique skill set and home park factors. None more so than for the Giants, who will need to improve their OBP from last season and ask more in terms of hard-hit fly-balls at AT&T Park from both their shiny new righties and their existing ones. Away from home, where they already hit 33% of balls in the air, they can all afford to hit more. Not so much a fly-ball revolution for the Giants, perhaps, more of a fly-ball evolution.

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