Mar 9, 2014; Jupiter, FL, USA; Miami Marlins right fielder Giancarlo Stanton (27) puts the ball in play against the Detroit Tigers at Roger Dean Stadium. Mandatory Credit: Scott Rovak-USA TODAY Sports

Simple Sabermetrics: How to Project Home Runs

A problem with sabermetrics is that they often lack utility.

For a guy who is used to flipping over a baseball card, a stat like FB% can seem pretty nonsensical. It’s not at all a junk stat, but it’s just that it doesn’t feel actionable to the average fantasy baseball player. Sure, I can look up a player’s HR/FB rate, but how the heck does it help me win my fantasy baseball league?

Using saber metric statistics for the purpose of predicting future home run output is pretty easy business. I’ll take you step-by-step with 3 simple indicators. (In fact, I’ve done this with both Chris DavisHERE – and Giancarlo StantonHERE – as examples.)



Fly ball rate – FB% – is the percent of balls a batter hits into the air. A ground ball can’t leave the yard, so fly balls are of critical importance to a power hitter.

Every hitter has what’s called a batted ball profile. Let’s say the batter knocks 100 balls into play, because, man, pretending it’s an even hundred makes thinking about percentages really easy.

The player’s batted ball profile would be how many of those 100 balls were:

  1. Popped up into the infield: His Infield Fly Ball Percentage (IFFB%)
  2. Hit as a grounder: His Ground Ball Percentage (GB%)
  3. Hit on a rope as a line drive: His Line Drive Percentage (LD%)
  4. And the ones hit as long fly balls: His Fly Ball Percentage (FB%)

Infield popups are always bad, bad, bad, while grounders are fine if you are a speedy little runner like Billy Hamilton. Line drives fall for hits into the gaps often, so they lead to high batting averages.

But it’s the fly balls that lead to home runs, so power hitters tend to hit the ball into the air more.  This may seem obvious, but many fantasy owners miss this.

For example, fantasy owners become frustrated because Joey Votto doesn’t hit 30 home runs, but if they’d look at his 29.2 FB% and compare it to Chris Davis’ 45.7 FB% they begin to understand that it’s more reasonable to expect 24 home runs out of Votto.



But it’s not enough to just hit the ball into the air. In order to be an effective home run hitter, you need to hit a large portion of those fly balls over the fence. Home Runs per Fly Ball – HR/FB – is the percentage of those fly balls that clear the fence.

Keep in mind that league average HR/FB rate is about around 10%. Ever been to a baseball game and noticed how those lucky jackwagons right behind home plate jump to their feet because they think that every high fly ball is a home run?

“Oh! Oh! Oh!    Awwwww…”

Yeah, only about 1 out of every 10 of those fly balls actually turn out to be home runs.

It is also important to know the HR/FB levels out around 300 plate appearances. Why is this important? Well, it can also help you identify players mid season who may be over or under performers.

Compare a player’s HR/FB to his career norms. If a player’s early season HR/FB percentage is well above his career norm, then his home runs will most likely cool down during the second half. On the flip side, if a power guy is barely over the league average of 10%, then expect that he’ll start knocking them out soon.

As way of example, let’s still assume 100 batted balls, 40% of which go as fly balls (40% FB%). That’s 40 fly balls. Now let’s say the batter’s HR/FB is the league average of 10%. Then 4 of those 40 went for home runs.


“Lucky” Home Runs

Lastly, we’ll use our hit tracker tool. This is important because every major league ballpark has different dimensions. The fly ball that found it’s way of the right field dense in Yankees Stadium might fall at the warning track in another, more spacious stadium.

We can look to average fly ball distance as a helpful tool here. You can find that at the excellent Baseball Heat Maps.

Bit it’s simpler just to take a peek at how many of a batter’s home runs are “lucky”, and that is done with the equally excellent Hit Tracker Tool.

Search any player and the Hit Tracker will tell you how many of his home runs were:

  1. “No Doubts”, meaning they were absolutely launched and would’ve flown out of any stadium.
  2. “Just Enoughs”, meaning they landed a couple rows into the outfield bleachers.
  3. “Lucky Homers”, meaning they just squeaked over and probably would’ve fallen short in a large stadium.

The Hit Tracker is a handy tool and it will allow you to spot players that may have seen their home run totals rise, but it turns out that many of them were just “lucky.”


So that’s the basics of using some simple sabermetrics to project future home runs. If you are interested in some examples, you can read about Chris Davis or Giancarlo Stanton.

You can also find some more Simple Sabermetrics here: OBP, FIP, ISO, Plate Discipline, Command Ratio, and Predictive Stats.

Tags: Chris Davis Fantasy Baseball Giancarlo Stanton Home Runs MLB Sabermetrics

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