The Ideal Groundball Rate for Hitters, Featuring the Royals

Is there an ideal ground ball rate for hitters? Should they be thinking about how many grounders they hit? Armed with some spreadsheets and a couple conversations with some Royals’ hitters, let’s see what we can discover.

First off, we can write off a simple answer. There is no correlation between ground-ball-to-fly-ball ratio and team runs scored or team weighted runs created. Teams are made up of individuals, and it might be folly to recommend one approach to Billy Butler as you would to Jarrod Dyson. Perhaps that’s partly what Eric Hosmer meant when he told me that you don’t want to “change too much from the natural fluidity of you swing — you got to this level with that swing.”

But we’ve been taught the adage that more fly balls mean more home runs. Billy Butler acknowledged he’s heard that before. And of course your ground-ball-to-fly-ball ratio is strongly (and negatively) correlated to power stats — more fly balls do mean more home runs. And also the relationship between ground-ball-to-fly-ball ratio and batting average on balls in play is fairly clear — more grounders mean more hits. The value of the home run outstrips the value of a hit, and that’s why GB/FB ratio is not well correlated to runs, or overall offensive value.

A cursory look at the fly ball leaderboard since 2003 shows multiple entries from Frank Thomas, Mark Reynolds, Jason Giambi and Jose Bautista. Even if ground balls turn into hits more often, the fly ball serves the slugger well, so sluggers turn to it more.

So it looks like there might be an ideal ground-ball-to-fly-ball ratio… for each individual hitter. We’re back to Hosmer’s quote about each individual swing, with an asterisk. Billy Butler talks about thinking only of “putting the barrel to the ball” when he’s at the plate, but there do seem to be variations on that theme for different types of players. Sluggers get the ball in the air a bit more, and speedsters put it on the ground.

Players do change, and players do search for a unique mix that works for them. Perhaps they were sluggers before but find themselves dwarfed by the sluggers in the big leagues. Perhaps they’d like a few more hits mixed in with their home runs.

Joey Votto talked about leveling his swing plane. Alex Gordon had much of the same revelation, brought on by his early struggles and his demotion in 2010. “Over the last couple of years I’ve tried to cut down on my fly balls and I’ve tried to cut down on my strikeouts,” he said, “because the easiest out in baseball — other than the strikeout — is the lazy fly ball.”

It’s hard to argue with his results. He’s progressively hit more ground balls, and his offense is a career-high 44% better than league average right now. It looks like ground balls (and fewer strikeouts) drove much of his improvement:

Year BB% K% ISO OBP Pull% GB/FB wRC+
2007 6.8% 22.8% 0.164 0.314 41.3% 0.85 87
2008 11.6% 21.0% 0.172 0.351 42.2% 0.66 106
2009 11.1% 22.8% 0.146 0.324 39.8% 1.04 87
2010 12.1% 22.1% 0.140 0.315 43.2% 0.96 85
2011 9.7% 20.1% 0.200 0.376 43.8% 1.03 141
2012 10.1% 19.4% 0.160 0.368 36.4% 1.29 126
2013 5.3% 20.5% 0.189 0.373 36.9% 1.45 144

And the park means something. “In a big stadium like Kaufmann, a lot of fly balls just go to the warning track,” Gordon said. Even a unique hitter struggling to find the best ratio with respect to his own game might have to think about the park he calls home more often. Jed Lowrie mentioned this when he talked about the evolution of his swing in the different organizations and parks he found himself in. You don’t want to change your swing to suit your park too much — what if you get traded — and yet you play half your games there. Home runs are suppressed by 16% with respect to the average park in Kansas City, and yet the White Sox call The Cell home, which augments home runs by 24% over average. Maybe, when Gordon talks about how he “got carried away with hitting home runs” early in his career, maybe he wouldn’t have changed his swing like he did if he played in Chicago.

Can we see the difference starkly? On the left is a swing from 2008, when Gordon had one of his higher pull percentages and lowest ground-ball rates, and HD apparently didn’t exist. And on the right, the first of his four hits from his strong night against the Athletics on the 19th.


Maybe Alex Gordon has found his own unique ideal ground-ball rate. He’s certainly calmed his pre-swing movement down, and his swing plane looks more level. And you can see he’s right when he says he’s now more capable of covering the outside corner more now that his swing is more level and he’s not concentrating on pulling the ball. Gordon credits former hitting coach Kevin Seitzer for the advice, but he put in the hard work. He’s no longer “see the ball, hit the ball, try to crush the ball” as he used to be.

There’s one last asterisk here: the pitcher. Hitting coaches talk about hitting the ball where it is. Eric Hosmer called it “playing the situation, whatever it is that at-bat.” Alex Gordon said he is always “thinking about what the pitcher is trying to do.”

But we sort of know what the average pitcher is trying to do. Thanks to Jeff Zimmerman, we know 61% of all pitches are on the outside half of the plate. 45% of the pitches in the strike zone are in the bottom third of the zone. Butler said he’s always “looking from the knees to the waist because pitchers are taught to get outs at the knees.” There’s Gordon talking about the added plate coverage he has now. These are potentially good arguments for most hitters to consider a more level swing plane across the board.

Even if there is an argument for more ground balls, there isn’t quite an argument that there is one ideal ground-ball-to-fly-ball ratio for all hitters. Each has to find their own unique mix. For some, it might take a little time and some tweaks. For others, they’re just naturally able to barrel the ball from day one. But that relationship — between how level your swing is, and the amount of ground balls you produce — looks like a place you might start if you were struggling at the plate. It certainly worked for Alex Gordon.

Update: I took out a graph showing a negative correlation between HR/FB and GB/FB ratio because it really just was a graph of a correlation between GBs and HRs, and that’s obvious. Sluggers like to hit more fly balls!

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Graphs: Baseball, Roto, Beer, brats (OK, no graphs for that...yet), repeat. Follow him on Twitter @enosarris.

17 Responses to “The Ideal Groundball Rate for Hitters, Featuring the Royals”

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  1. Jason says:

    Interesting article. The correlation between pull rate and ground ball rate is interesting but not suprising. Hitters who look to pull the ball are usually doing so to hit more home runs, so higher pull rate correlating with fly ball rate would be expected. The take what the pitcher gives me, cover the outside, and meet the ball with a nice level swing approach obviously is working for Gordon this year who would be an MVP candidate in the AL in a world with no Miguel Cabrera. If only some of his magic could rub off on the statistically worst hitting infield in baseball and now that Salvador Perez is hurt, a team with only 3 batters that make you nervous (Gordon, Butler, Cain).

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  2. Alan says:

    On the flip side of tailoring your swing to a park, Chase Headley credits going back to his minor league swing for his breakout. Even with 50% of your games in an extreme park like Petco, are massive park adjustments really necessary?

    If you’re a 30 home run guy, 15 of those are at home, and if your park affects them by 10%… do you really completely alter your swing because 1-2 HRs become outs?

    Minor tweaks might be great, but are they practical in terms of how a player has to change? Giant tweaks for park purposes seem like they’d be overkill.

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  3. JKB says:

    Thought provoking article.

    The table with Gordon’s yearly stats shows what appears to be a threshold K% 100. I wonder if this applies more generally to other players/teams or if varies from player to player, team to team, or player “type” to player “type”.

    Also, the first graph of HR/FB vs. GB/FB probably looks a lot the graph of HR vs. GB (without dividing by FB).

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    • Eno Sarris says:

      Yeah I thought that but the work I didn’t show for my second and third paragraphs was all done with GB/FB ratio so I stuck with it for consistency.

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  4. JKB says:

    What I wrote above was that the table with Gordon’s yearly stats shows what appears to be a threshold K% of twenty one percent. Not sure why twenty one percent got changed to 100. Thanks again for the thought provoking article

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  5. LEC says:

    JKB mentioned this above, but you cannot take anything away from the comparison between HR/FB and GB/FB. If you increase the number of flyballs hit then both ratios must decline; therefore, the simple correlation between the two has to be negative.

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    • Eno Sarris says:

      Ugh that’s an even worse way of putting it. Well, still saying that home run hitters hit more fly balls is the point either way. It’s an obvious one, but it makes sense to make it within the context of the article.

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      • LEC says:

        Still good work as always, love reading the site. Just thought it was worth pointing out.

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  6. channelclemente says:

    Maybe Gordon just abandoned the odd point of view of ‘backspinning a ball out’, whether purposefully or by accident.

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  7. Josh says:

    Great work Eno, very interesting read. Looks like he is breaking out given the information above. However, despite the work Gordon has put into his swing, do you think he is a regression candidate at this point? His BABIP is incredibly high and he’s hitting less line drives. Most worrying is the fact that he his walking considerably less than last year and making slightly worse contact. Those are some worrying signs but maybe he’s legit after all?

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    • rbt says:

      Alex Gordon, after a lot of work to change is stance and approach, is a fair distance into his third year of “doing it.” I think it’s time to quit asking if he is legit or not.

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  8. Wobatus says:

    If players are tailoring their swing to their home park that may exaggerate the park effect..

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    • adohaj says:

      Maybe park effects exist not because of the park dimensions themselves but because of hitters adjustments to the park dimensions.

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  9. baseballfan says:

    I’m not a Royals fan, but I am a baseball fan.

    I watched a game the other night, and saw in the bottom of the 9th, with the Royals trailing, Hosmer came to the plate. He worked the count in his favor, and got a pitch around mid-thigh, middle to inner third of the plate. He shot it the other way for a base hit, and looked as though he was proud of himself. I was not impressed by this. This is generally a lefty’s power zone. He turned himself into a slap hitter, when his team needed power.

    It made me wonder if the Royals’ hitting coach was TOO concerned with Hosmer beating the shift, rather than being a slugger. That pitch would have been deposited into the seats by him in right in 2011, or by Harper, Fielder, insert any left handed slugger here.

    So, I started wondering if this is a general philosophy for the Royals hitters, which would obviously fall on the hitting coach, because I have looked at box scores and continue to see where Hosmer AND Butler are grounding out seemingly all the time. After last year’s power breakout for Butler, that is very disappointing.

    Because I am not a Royals fan, I do not get to watch many games. Can anyone tell me if these guys are grounding out much more this year than in the past, or if I’m just looking at a small sample?

    If so, when is the hitting coach held accountable?

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  10. Citizen James says:

    I’m not so sure a higher ground ball rate is contributing to Gordon’s recent success. Per Baseball Reference’s Hit Trajectory, Gordon has hit .247 on groundballs for his career — and .242 last season — while hitting an astounding .260 on flyballs for his career ( This season Gordon is hitting an unsustainably high .368 on groundballs (; this is the biggest reason why his offense is currently 44 percent higher than league average.

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  11. Dan says:

    Old thread, but I’m curious why a pitcher’s ability to get ground balls is emphasized so much nowadays. As you said, there is “no correlation between ground-ball-to-fly-ball ratio and team runs scored or team weighted runs created”. Is it simply because there is a slight correlation to earned runs, and if so, who cares if it doesn’t lead to more runs overall?

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