FanPost

Homerun Differential and the Playoffs

Big Bomb. - USA TODAY Sports

In Tuesday's game summary thread there was some discussion of the Royals homerun differential. They were sitting, at the time, at -11. Billy Butler and Jeff "Freedom" Francouer bashed two in Wednesdays game to make that differential -9 which would put them tied at 25th with Tampa and LAD. Certainly with this crew consisting of Santana, Guthrie, and Shield, all pitchers notorious for giving up the long ball (ranked 2nd 3rd and 4th in HR allowed the past 4 years; thanks to Old Man Duggan), keeping the ball in the park is going to be essential for having a low ERA and in turn forcing the Royals to score less runs to win. In this brief study we'll take a look at a teams home run differential and it's impact with making the playoffs.

So to see how homerun differential impacts a teams chances of making the playoffs we'll use playoff teams from 2010-2012. We'll then take the teams homeruns hit and subtract their homeruns allowed and voila you've got their homerun differential. Pretty easy equation.

2012

  • Nationals: 194 HR hit - 129 HR allowed = +65
  • Yankees: 245 HR hit - 190 HR allowed = +55
  • Athletics: 195 HR hit - 147 HR allowed = +48
  • Orioles: 214 HR hit - 184 HR allowed = +30
  • Cardinals: 159 HR hit - 134 HR allowed = +25
  • Rangers: 200 HR hit - 175 HR allowed = +25
  • Reds: 172 HR hit - 152 HR allowed = +20
  • Tigers: 163 HR hit - 151 HR allowed = +12
  • Braves: 149 HR hit - 145 HR allowed = +4
  • Giants: 103 HR hit - 142 HR allowed = -39

Team Home Run Leader: Yankees (see above)

Team Home Run Allowed Leader: Blue Jays - 204 HR allowed with a HR Diff of -6 (finished 73-89)

2011

  • Yankees: 222 - 152 = +70
  • Rangers: 210 - 170 = +40
  • Brewers; 185 - 147 = +38
  • Phillies: 153 - 120 = +33
  • Cardinals: 162 - 136 = +26
  • Tigers: 169 - 149 = +20
  • Diamondbacks: 172 - 159 = +13
  • Rays: 172 - 161 = +11

Team Home Run Leader: Yankees (see above)

Team Home Run Allowed Leader: Orioles - 210 HR allowed with a HR Diff of -19 (finished 69-93)

2010

  • Reds: 188 - 158 = +30
  • Giants: 162 - 134 = +28
  • Yankees: 201 - 179 = +22
  • Braves: 139 - 126 = +13
  • Rangers: 162 - 162 = 0
  • Rays: 160 - 175 = -15
  • Twins: 142 - 155 = -13
  • Phillies: 166 - 168 = -2

Team Home Run Leader: Blue Jays - 257 HR hit with a HR Diff of +102 (finished 85-77)

Team Home Run Allowed Leader: Diamondbacks - 210 HR allowed with a HR Diff of -30 (finished 65-97)

Some conclusions:

  • You don't have to have a positive HR differential to make the playoffs... but it really helps. Only 5 teams out of 26 (19%) have made the playoffs in the past 3 years with a neutral or negative HR/Diff.
  • Obviously if your team gives up more home runs than any other team you're going to have trouble winning games.
  • Not allowing home runs is as important as hitting them as well. While you are pretty much guaranteed a losing record if you allow vast amounts of dingers, you are almost guaranteed a winning record if you prevent them too.

Home Run Allowed Leaders:

  • 2009: Orioles - 218 (64-98)
  • 2008: Reds - 201 (74-88)
  • 2007: Astros - 206 (73-89)
  • 2006: Orioles - 216 (70-92)
  • 2005: Reds - 219 (73-89)

Home Run Prevented Leaders:

  • 2012: Dodgers - 122 (86-76)
  • 2011: Giants - 96 (86-76)
  • 2010: Braves - 126 (91-71)
  • 2009: Braves - 119 (86-76)
  • 2008: Dodgers - 123 (84-78)
  • 2007: Padres - 119 (89-74)
  • 2006: Dodgers - 152 (88-74)
  • 2005: Marlins - 116 (83-79)

Obviously park factors play a huge part in total home runs prevented.

Some outliers in the HR prevented records:

  • 2005: Despite allowing 2 less home runs than the 100-62 Cardinals, the Giants finished 75-87.

The Giants had a -23 HR/DF and the Cardinals had a +17 HR/DF

  • 2006: Pirates allowed 2 less than the 89-73 Angels and 4 less than 95-67 Detroit but finished 67-95

Pirates: -15 HR/DF

Angels: +1 HR/DF

Tigers: +43 HR/DF

  • 2007: Dodgers allowed the exact same amount of HR as 96-66 Indians but finished 82-80

Dodgers: -17 HR/DF

Indians: +32 HR/DF

  • 2008: Athletics allowed 8 less home runs than the 89-73 but finished 75-86

Yankees: +37 HR/DF

A's: -10 HR/DF

  • 2009: Royals prevented 1 less home run than the 95-67 Red Sox while the Padres allowed the exact same but both teams finished 65-97 and 75-87 respectively.

Red Sox: +45 HR/DF

Padres: -26 HR/DF

Royals: -22 HR/DF

  • 2010: Mets allow 1 more home run than the 92-70 Giants but finish 79-83

Giants: +28

Mets: -7

  • 2011: Twins allow the same amount as 91-71 Rays but fall to 63-99

Rays: +11 HR/DF

Twins: -58 HR/DF

  • 2012: Despite allowing the same amount of home runs as the Red Sox the Yankees finish 95-67 instead of 69-93 like Boston.

Yankees: +55 HR/DF

Red Sox: -25 HR/DF

Note: The AL teams are at a disadvantage with allowing home runs due the DH as the home runs prevented leaderboard is generally stacked with NL teams at the top.

It's a pretty basic theory. You hit more home runs than you allow and you'll probably have a good record. Is there a correlation to home run differential and the playoffs? I don't think so. I haven't been able to find a magic threshold of "~HR/DF of X = playoffs" but certainly teams with positive HR/DF generally fare better than those with negative ones.

For the Royals sake they'll probably need to be near at least a neutral HR/DF given that they are in the AL and are susceptible to giving up more bombs with the DH in play.

Kauffman does a pretty good job of suppressing home runs and generally rates below average in HR allowed. (15th best in 2012, 2nd best in 2011, 12th in 2010).

Similar HR parks:

2012

  • Target Field: 1.031 - Twins HR/DF: -20 (66-96)
  • Rogers Centre: 1.030 - Jays HR/DF: -6 (73-89)
  • Kauffman: 1.028 - Royals HR/DF: -32 (72-90)
  • Comerica: 1.026 - Tigers HR/DF: +12 88-74

2011 (using Fangraphs Park Factors instead of ESPN)

  • O.Co Coliseum: 93 - A's HR/DF: -22 (74-88)
  • Target Field: 92 - Twins HR/DF: -58 (63-99)
  • Kauffman: 92 - Royals HR/DF -34 (71-91)
  • Busch Stadium: 91 - Cardinals HR/DF: +26 (90-72)
  • Petco Park: 90 - Padres HR/DF: -34 (71-91)

2010

  • O.Co Coliseum: 93 - A's HR/DF: -44 (81-81)
  • Target Field: 92 - Twins HR/DF: -13 (94-68)
  • Kauffman: 92 - Royals HR/DF -55 (67-95)
  • Busch Stadium: 91 - Cardinals HR/DF: +17 (86-76)
  • Petco Park: 90 - Padres HR/DF: -7 (90-72)

So it's possible for a home run park similar to Kauffman to have a negative HR/DF and still have a winning record, but of course it takes good pitching like the Cardinals had, a park that kills offense really well like San Diego, or a team with a Triple Crown winner and another 30+ homerun hitter like the 2012 Tigers.

I'd put the O/U on the Royals HR/DF for a 85+ win season as having to be no greater than -20. Right now they are sitting at 6-3 and a -7 HR/DF.

This FanPost was written by a member of the Royals Review community. It does not necessarily reflect the views of the editors and writers of this site.

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