A lot of times, those of us in “the know” toss out numbers, and sometimes worse acronyms, expecting that folks will understand what we’re talking about. Sometimes that’s fine. Other times, though, we’re doing you all a disservice. This piece is an attempt to start to rectify that issue. I will talk about ground ball rates, fly ball rates and home run ratios in this piece. Never say I’m not a nice guy. Negative, sure, but I’m still helpful. At least I think I am.

THE GROUND BALL

A ground ball is hit on about 45 percent of batted balls.

THE FLY BALL

A fly ball is hit on about 34 percent of batted balls.

GROUND BALL TO FLY BALL RATIO

1.32 was the league average in 2015.

HOME RUN TO FLY BALL RATIO

The HR/F ratio league average last season was 11 percent.

Those are the ratios you need to know for the four measures. Let’s dig a bit deeper.

Point No. 1 – Players establish their own baselines in all the measures. Some batters are always hitting 55 percent of their batted balls into the ground while some players are at 40 percent. The same is true for fly balls as well. The league average is there as a guide, but you have to factor in the type of hitter the player is.

Points No. 2 – With a large enough sample size most players post a similar number year after year (a month isn’t long enough. In many cases, half a season might not be enough). A player can shift his game a bit – it’s widely understood that many players learn how to lift the ball as their careers go on, meaning as they get older they hit the ball more frequently in the air. Note I use the term “a bit.” If a player is a 35 percent fly ball man and all of a sudden he’s at 47 percent we have a decision to make.

(A) Has he changed his approach? (B) Is he hurt, causing his swing path to change? (C) Has the player lost bat speed, due to age or injury or because of bad mechanics, which is causing him to drag the bat through the zone leading to more lazy fly balls? Bottom line here is if there is a drastic shift you should dig deeper to see if you can explain the shift. Conversely, if a fly ball hitter is all of a sudden beating the ball into the ground, there might be an issue beyond just a change in approach.

Point No. 3 – While line drives turn into hits more than any type of batted ball it should also be mentioned that ground balls become hits more frequently than fly balls. In most cases that means guys that hit the ball on the ground are more likely to be solid batting average contributors than guys who hit a lot of balls skyward. Flipside, the men that drive the ball into the air more effectively obviously hit more homers and often have larger RBI totals. Generally, of course. Here’s the breakdown:

Line drives are hits about 70 percent of the time.
Ground balls are hits about 20 percent of the time.
Fly ball are hits about 11 percent of the time.

Let’s look at each of the three categories in a bit more depth.

  • Note: We are using 502 plate appearances and the baseline for the discussion since that is the number of plate appearances needed to qualify for the batting title.

GROUND BALLS

Last season there were eight men with a ground ball rate above 55 percent. Even with 500 at-bats or more it will be nearly impossible for these type of hitters to reach even 20 homers. They just don’t hit the ball in the air enough. Moreover, 15 can be a challenge.

62.5 Christian Yelich
59.8 Dee Gordon
59.0 Jean Segura
57.9 Cameron Maybin
57.2 Jason Heyward
56.2 Andrelton Simmons
55.7 Joe Mauer
55.5 Wilson Ramos

Ideally you want extreme ground ball types to be fast as all get out, which explains why guys like Simmons and Mauer are pretty useless in fantasy.

There were nine men who had a ground ball rate of less than 34 percent:

27.4 Lucas Duda
29.7 Matt Carpenter
30.8 Curtis Granderson
31.8 Chris Davis
32.5 Brandon Moss
33.1 Todd Frazier
33.3 Brandon Belt
33.3 Brian Dozier
33.9 Ian Kinsler

FLY BALLS

Only one man had a fly ball rate over 50 percent but there were six men over 45 percent:

50.6 Lucas Duda
48.8 Jose Bautista
47.7 Todd Frazier
47.2 Brian McCann
47.1 Brandon Moss
45.2 Kris Bryant

The Cubs rookie, Bryant, was the only man to hit over .260. He finished at .275. Remember, fly balls end up as hits the least frequently of the batted ball types.

Those men who didn’t lift the ball at all:

15.0 Christian Yelich
18.7 Dee Gordon
18.9 Ben Revere
19.5 DJ LeMahieu
20.0 Cameron Maybin
22.4 Andrelton Simmons
22.7 Starling Marte

Marte is an interesting case given that he hit the seventh fewest fly balls of any full-time player in baseball last season, yet still almost hit 20 homers as he finished with 19. Read on to find out how that happened.

HR/F RATIO

The league average last season was 11 percent.

If you want to just remember a handy reference think 10 percent.

A key point with this measure is that players set their own baseline. Guys that are eight percent year after year don’t suddenly turn into 19 percent guys, just like a guy who is at 18 percent year after year shouldn’t dip to nine percent. Both of those things do happen, though, guys surging and falling, but the truth is that they almost always regress to their personal norm, especially in the case of extreme stuff. Here are some 2015 numbers:

One man was at 30 percent – Nelson Cruz at 30.3 percent. No one ever repeats a 30 percent mark. Just doesn’t happen.

In fact, a number of 25 percent is massive and more often than not a little pullback is likely even when a slugger reaches that level. Only four other were at 25 percent in 2015: Chris Davis (29.4), Bryce Harper (27.3), Carlos Gonzalez (25.8) and Mike Trout (25.3). Now, let’s take a look at all five men by comparing their 2015 number to their career mark. Note that all five men exceeded their career marks in 2015.

18.8 Cruz (gained 11.5 percent in 2015 compared to his career rate)
23.8 Davis (gained 5.6 percent)
20.0 Harper (7.3 percent)
19.7 CarGo (6.1 percent)
19.7 Trout (5.6 percent)

It is more likely than not that all will see a regression in their HR/F ratio in 2016. No one else in baseball reached 22.5 percent in 2015.

A rolling three-year average, meaning looking back at 2013-15, is a pretty good judge of what to expect in most cases in 2016.

As for Marte, who was mentioned above, his HR/F exploded in 2015. After two years with a mark of 12.5 percent he gained roughly 50 percent all the way up to 18.6 percent in 2015. Just 27 years old, it’s certainly possible he will be able to at least hold on to some of that growth, if not all of it. At the same time it is discouraging that his fly ball ratio fell from 28 percent in 2013-14 to under 23 percent last season. It would be reasonable to expect him to hit more fly balls in 2016 with a lower HR/F ratio with the end result being a very similar level of home run production in the coming season.

Finally, let’s take a look at a few men that should see an increase in their HR/F ratio in 2016.

Gregory Polanco was at 5.5 percent. Double that number and you would only be at the league average. His GB/FB ratio was 1.30 last season, another league-average mark.

Evan Longoria has been at 10.8 percent each of the last two seasons but his career mark is 14.8 percent and in 2013 the mark was 15.7 percent. He’s only 30 years old.

Mark Trumbo was at 12.5 percent last season and 12. Percent in 2014. Still, he will be 30 on Opening Day, owns a career 17.9 percent mark, posted a 20.9 percent rate in 2013 and moves to a solid hitting park in Baltimore.