Miller Park Myth: Ground Ball Ratios at Home, Overall | Disciples of Uecker

Disciples of Uecker

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Feb 21, 2016; Maryvale, AZ, USA; Milwaukee Brewers starting pitcher Matt Garza (22) fields ground balls during spring training camp at Maryvale Baseball Park. Mandatory Credit: Rick Scuteri-USA TODAY Sports

Matt Garza, 2016’s team leader of inducing ground balls, practices to make sure he can field one himself.  Credit: Rick Scuteri-USA TODAY Sports


It is a common theme to hear from writers and fans: ground ball pitchers are ideal to have in the Miller Park environment.  The topic appears to make sense, as our home stadium leans towards favoring offensive abilities compared to pitchers.  Statistically-speaking, the more a pitcher keeps the ball on or near the ground, the more likely it is to be recorded an out or a single (rather than for extra bases).  It would also allow for more double plays to get out of tough binds one might find himself in.  But are ground ball ratios a single statistic to monitor and analyze to determine the ability for success? I’ll take a look at individual starters, relievers, and overall team statistics to find out.

Starter GB Numbers

Player IP ERA GB/FB K GB ratio FB ratio
Jimmy Nelson 179.1 4.62 1.58 140 49.4 31.3
Zach Davies 163.1 3.97 1.40 135 45.5 32.5
Chase Anderson 151.2 4.39 0.88 120 36.1 41.1
Wily Peralta 127.2 4.86 1.82 93 50.0 27.5
Junior Guerra 121.2 2.81 1.26 100 45.3 35.8
Matt Garza 101.2 4.51 1.96 70 54.8 28.0
Taylor Jungmann 26.2 7.76 1.23 18 44.7 36.5

What we’re looking at is the majority spread of where the ball ends up once it is hit  – omitting line drive ratio due to its level of subjectivity to the recorder.  But there are a few things we can discern from the table.  At the onset, we see the starting rotation being geared towards ground-ball tendencies – with exception of Chase Anderson (who actually owned higher ground ball rates in Arizona).  In fact, Anderson would be the only one on the list to be considered as a “fly-ball pitcher” due to his FB ratio reaching over 40%.  But the ground ball rates – as positive as they are – don’t appear to give a player a ton of success during the season by themselves.  Only Junior Guerra and Zach Davies owned ERA’s lower than 4.00, and they had some of the lower ground ball rates (though they are all above neutral). But if one were to bring into a somewhat popular assumption that these pitchers would fare better in Miller Park if their ground ball ratios increased, you might be correct – depending on what the splits tell us.

Starter GB Rates at Home

Player IP ERA GB/FB K GB ratio FB ratio
Jimmy Nelson 95.1 3.40 1.5 74 48.2 32.6
Zach Davies 108.0 3.75 1.4 95 45.6 33.5
Chase Anderson 73.0 3.82 0.8 62 34.1 42.7
Wily Peralta 72.1 5.23 1.6 57 49.5 31.2
Junior Guerra 60.2 2.23 1.3 45 45.2 36.1
Matt Garza 45.1 3.38 2.1 35 56.1 27.3
Taylor Jungmann 14 3.86 2.1 7 59 28.2

The numbers at home in comparison to their seasonal statistics don’t fair as well as one would think.  On a positive side note, it’s wonderful to see them all pitching better at home than they do everywhere else, especially since they play 82 games in Miller Park.  Jimmy Nelson benefited most from pitching at home, but the 0.8 difference in favor of ground balls may not make that much of a difference to his ERA (his walk-rate, opponent batting average, and strand-rate were also much improved).  Davies’ 22-point drop in ERA doesn’t appear to be due to an increase in ground balls, but rather in his lower amount of walks at home (1.92 BB/9 vs. 2.44 away).  The same certainly cannot be said for Anderson, who actually improved with a lower ground-ball rate at home.  Guerra’s ground ball increase could have been a factor in his .48 (!) drop in ERA despite the slight increase in fly-ball rate.  But what was more surprising about Guerra was the drop in total strikeouts at the expense of more balls being hit in-play, as well as an increase in hard-hit rate (37.4% at home vs. 30.3% away).  His BABIP, which was sitting around .246 at home (.300 being around normal), appears to indicate he got incredibly lucky when it came to the increase in success.  Both Wily Peralta and Taylor Jungmann had (literally) up-and-down seasons, but the former owned higher marks in GB/FB upon the beginning of his second-half streak (1.8), which helped to garner that red-hot 2.87 ERA from August onward at home.  The latter – who pitched in only 14 innings – appeared to have benefited despite the lack of innings compared to others.  The lone shining spot for ground ball rates comes in Mr. Matt Garza – who was also helped by an increase in K/9 and decrease in opponent batting average (.237).

In nearly every instance, we see an improvement on the part of the starting rotation when they pitch at home, but it really doesn’t appear to be inextricably caused by ground ball ratios.  In some cases, they even improved with a small dip in ground ball numbers.  But what about the bullpen?

NOTE: I’ll be omitting the small-fries (less than 15 innings pitched).  My apologies go out to David Goforth, Sam Freeman, Damien Magnifico, Ben Rowen, Neil Ramirez, Ariel Pena, and Michael Kirkman.

Relief Numbers (Home Splits):

Player IP ERA GB/FB K GB ratio FB ratio
C. Torres 82.1 (40.2) 2.73 (3.32) 1.29 (1.1) 78 (38) 44.6 (41.4) 34.7 (36.0)
T. Thornburg 67 (35.2) 2.15 (1.77) 0.72 (1.15) 90 (51) 32.4 (41.1) 44.8 (35.6)
B. Boyer 66.0 (37.1) 3.95 (2.41) 1.69 (1.85) 26 (14) 44.8 (48.8) 32.4 (26.4)
J. Marinez 58.2 (22.2) 3.22 (3.27) 1.89 (1.88) 47 (25) 49.7 (52.5) 26.3 (27.9)
J. Jeffress 44.2 (27.1) 2.22 (3.29) 3.29 (3.00) 35 (25) 57.7 (54.2) 17.5 (18.1)
M. Blazek 41.1 (23.2) 5.66 (6.85) 1.02 (1.07) 36 (19) 40.6 (40.0) 39.8 (37.5)
C. Knebel 32.2 (16.1) 4.68 (3.86) 1.15 (1.06) 38 (20) 42.2 (41.5) 36.7 (39.0)
T. Cravy 28.1 (9.2) 2.86 (0.93) 0.49 (0.42) 22 (9) 24.4 (22.7) 50.0 (54.5)
J. Barnes 26.2 (11.1) 2.70 (4.76) 1.59 (1.36) 26 (13) 48.6 (51.7) 30.6 (37.9)
C. Capuano 24.0 (8.2) 4.13 (5.19) 1.04 (1.22) 27 (7) 44.4 (45.8) 42.9 (37.5)
W. Smith 22.0 (11.0) 3.68 (5.73) 0.86 (1.10) 22 (12) 33.3 (36.7) 37.3 (33.3)
B. Suter 21.2 (8.2) 3.32 (0.00) 1.16 (0.67) 15 (5) 43.3 (32.0) 37.3 (48.0)
R. Scahill 18.1 (10.1) 2.45 (0.87) 3.55 (7.67) 14 (8) 68.4 (76.7) 19.3 (10.0)

Now this is where things get a little muddled.  There are certainly some players who have benefited from higher ground ball rates, but there is also a large mix of outcomes.  Out of the 13 names:

  • 6 of them saw an increase in ground ball rate at home, while 7 did not.
  • 3 of the 6 who had higher ground ball rates (Thornburg, Boyer, Scahill) had significant change in their numbers being at home.
  • 3 of the 6 who had higher ground ball rates (Blazek, Capuano, Smith) performed worse at home.
  • Of those 7 who did not, 3 (Knebel, Cravy, and Suter) posted worse ground ball rates with better overall production.
  •  3 of the same 7 who did not (Torres, Jeffress, Barnes) also did struggle more at home
  • 1 of the 7 (Jhan Marinez) had an incredibly close ERA and GB/FB ratio that could be caused to a bevy of other things.

What we can discern from this is the popular conclusion that a significant increase in ground ball ratios may indeed make an increase in production as a pitcher.  However, the closer we get between the differences of regular and home splits, the more muddled it gets.  The data is a near-even split when it comes to differences, which indicates that ground ball ratios are not an end-all, be-all statistic when we compare regular, individual player numbers to home splits within small sample sizes such as these.  In short, a small fluctuation of ground-ball rates between home and away don’t appear to single-handedly correlate with success.

In the same fashion, six of the seven starters own a positive GB/FB ratio, combined with 10 of 13 relievers.  This is shown in the team’s overall GB/FB rate – which was ranked within the top-10 of all 30 teams.

Season IP ERA GB/FB K BB GB ratio LD Ratio FB ratio
Brewers ’16 1434.1 4.10 1.39 1175 532 46.0 20.8 33.2
League Avg. 1443.2 4.19 1.29 1299 503 44.7 20.7 34.6
Rank 23rd 13th T-8th 28th 21st T-10th T-13th 7th

One thing I would like to point out around the league is the teams who ranked ahead of the Crew in GB/FB ratios.  The Cardinals, Rockies, and Pirates were the front three teams – all non-playoff teams.  Numbers 4 and 5 were the Cubs and Indians, respectively, then the Diamondbacks, Blue Jays, and Yankees (tied with MIL).  We see here a strange mix of some of the best teams meshed with much lesser teams.  To go along with that, the Red Sox (28th), Dodgers (25th), and Nationals (22nd) also made the playoffs despite below-average ground ball rates.  But all of these lower teams did rank highly in terms of overall K/9 (Dodgers #1, Nationals #2, Red Sox #10).

As we can tell from the numbers, the complete story of ground balls could significantly aid a team regardless of being home or away.  The Brewers finished with a 73-89 record, which was still in the bottom-10, but the game is never determined with just pitching.  The team ranked in the top-15 in overall ERA, as well as in ground ball ratio.  However the large decline in strikeouts means that the team had to field more often than the average MLB squad to record their outs.  Though we cannot completely say the pitching wasn’t at-fault for some losses, it appears as though it was a very strong point for the team in 2016.  But when we take a look at the splits themselves, we see something strange in terms of GB/FB.

Season IP ERA GB/FB K BB GB ratio LD Ratio FB ratio
2016 Home 743.0 3.76 1.39 629 261 46.2 20.5 33.3
2016 Away 691.1 4.47 1.39 546 271 45.9 21.1 33.1

Home Record: 41-40
Away Record: 32-49

Well, this is interesting.

A similar GB/FB ratio between home and away, and yet the team continued to perform better at home by nine wins.  Though the overall success of the team’s performance may have been influenced by the positive ground ball ratio, we see some other potential signs of issues with the team.  The increase in amount of strikeouts at home limited opponent’s opportunities to actually hit the ball in play.  The line drive ratio could also be a slight difference, as it means less potential to hit the ball for a base hit (as line drives typically fall for hits more often than fly balls or ground outs).  An increase in ground balls could have affected the amount of runners left on base, as the Crew stranded  74.8% at home compared to 71.9% away.  But what’s most glaring is that hard hit rate – a stark 4.3% difference between playing away from Miller Park. All of these factors are telling the story of the Brewers’ 2016 season on the mound – not just the ground ball rate in itself.

To bring it into the upcoming 2017 season, we might see a slight dip in what we saw in 2016.  The squad added both RHP Neftali Feliz and LHP Tommy Milone, who have both made the transition to becoming less fly-ball oriented in their games (though Feliz is relatively neutral, Milone more ground-ball oriented).  The ground-ball pitchers of Blaine Boyer, Tyler Thornburg, and Jeremy Jeffress are gone, and Knebel, Barnes, and Suter could take on some of the burden with Feliz.  We’ll continue to see Torres and Marinez in their roles, and might see some differences with Tyler Cravy (only 28.1 IP) and Michael Blazek (injured off-and-on).  This isn’t mentioning the prospects – the likes of Jorge Lopez, Josh Hader, Damien Magnifico, and Taylor Williams – who are wildcards in terms of how their tendencies.  And by observing the tendencies of winning clubs last season, the team’s focus could be focused on maintaining a higher K-Rate with a positive GB/FB ratio – something that Feliz, Hader, and Williams could definitely bring to the table.

In a nutshell, we can see that looking at ground ball rates alone can tell a pretty strange and confusing story when it comes to pitchers.  Players may find themselves performing with lower rates than we would expect them to, or perform better away from Miller Park.  But we can form three points out of the analysis: 1) An overall increase in ground ball ratios from the league average can point to better overall team performance, but 2) these same ratios should never be looked at on their own as a simple solution to determine a winning formula.  As for the Crew at Miller Park, the ground ball rates can help, but it certainly isn’t the only cause for success there.

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