Using Sabermetrics For Fantasy Baseball Part 6 - Pull%

Earlier in this series, we saw that fantasy owners generally prefer batters to hit the ball into the air in order to have a chance at a home run. Yet, all fly balls are not equal for this purpose. A player can maximize his power production by pulling the ball in the air.

Today we'll look at how to utilize Pull% for fantasy baseball analysis and, ultimately, win your 2018 fantasy baseball leagues.

If you aren't familiar with using sabermetrics to gain an advantage on your fantasy leaguemates, check in on the rest of our series. Learn how analyzing stats related to batted-ball distribution and more can help improve the performance of your fantasy baseball team entering the 2018 season.

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How to Interpret Pull%

In 2017, roughly 62% of all home runs were to the batter's pull side. Only 13% of homers went to the opposite field, with the remaining 25% going out to center. This distribution is fairly consistent year-to-year, so it's safe to count on going forward.

In a way, this makes intuitive sense. Pulled baseballs tend to be hit with the highest exit velocity, making it easier for them to leave the stadium. The power alleys next to the foul poles on either side of the ballpark also present the shortest distance to the cheap seats. If a player's HR/FB dramatically improves, a change in approach involving more pulled baseballs could help explain why.

Boston's Xander Bogaerts provides a good illustration of this kind of change. In 2015, he pulled only 16.7% of his fly balls, producing a HR/FB of 5.3% and a total of seven dingers. He significantly upped his power game in 2016 by pulling 28.1% of his flies, leading to a much higher 11.4% HR/FB and 21 bombs on the campaign. The increased power was not exclusively the result of the Pull% spike, as he upped his FB% as well (25.8% in 2015, 34.9% in 2016). It helped to validate his HR/FB increase, though.

Unfortunately, the change in approach did not last. Bogaerts pulled only 24.5% of his flies last season, dropping his HR/FB to 7.2% and his season HR total to 10 in the process. Once again, the raw number of fly balls Bogaerts hit decreased (30.5% FB%), so the change in Pull% was not solely responsible for the loss of power. This example illustrates that while a change in Pull% can support an increased HR/FB, it will last only as long as the player wants it to.

You should also avoid looking at raw Pull%. Of all pulled baseballs in 2017, 59.3% were grounders. Pulled grounders might have a higher average exit velocity than other ground balls, but the shift still eats them up with minimal difficulty. They will never turn into home runs. By contrast, only 21.3% of pulled baseballs were classified as fly balls last season. Ideally, fantasy owners want their hitters to pull fly balls while limiting how often they roll grounders to their pull side.

This is much easier said than done, as all players pull many more grounders than flies. Let's consider Giancarlo Stanton as an example. His raw Pull% of 44.6% was only marginally higher than the league average 39.8%, and he pulled 56.9% of his grounders compared to 32.6% of his flies. At first glance, you might think that Stanton was making himself vulnerable to the shift without significantly boosting his power potential.

That assumption would be wrong. The shift was designed for batters who pull much more than 56.9% of their ground balls, allowing Stanton to hit a solid .284 against it last year. Many batters fail to pull even 20 percent of their flies, so Stanton rated well above average in that regard as well. Stanton is the rare hitter who can go deep to any field, but 31 of his amazing 59 bombs were still pulled last year. Pulling more grounders than flies is far from a death sentence.

Conclusion

To sum up, pulled fly balls tend to perform better than other fly balls. This means that pulling more flies can produce an increased HR/FB, but you should never use raw Pull% to determine this. Most pulled balls are hit on the ground, where all of the exit velocity in the world cannot turn them into home runs. Therefore, you should filter a player's Pull% by batted ball type to produce the most reliable results. The next part of this series will look at lineup slot as a predictor of counting stats such as RBI and runs scored.