Toolshed: Evaluating Triple-A park factors

How to view prospect performances based on home/road splits

Steven Matz was arguably the best pitcher in the PCL this season before his promotion to the Mets. (Steve Spatafore)

By Sam Dykstra / | July 3, 2015 10:00 AM

This is part of a series of Friday columns we're calling the Toolshed, focusing on some of the more interesting prospect-centered storylines as the 2015 season develops. Have ideas, feedback or questions for Sam? Email him or tweet him @SamDykstraMiLB.

It was a common refrain last Sunday when Steven Matz made his Major League debut with the Mets. The 24-year-old left-hander posted a 2.19 ERA and 1.11 WHIP in 90 1/3 innings at Triple-A -- incredible given that he pitched for the Las Vegas 51s, whose Cashman Field is a supposed pitcher's graveyard. Noah Syndergaard had trouble there a season ago, posting a 4.60 ERA and 1.48 WHIP in 26 starts (133 innings). And as we know, Syndergaard's Major League numbers (3.59 ERA, 1.22 WHIP) have been better than that thus far. 

But just how much of a hitter's park is Cashman Field? And what about the rest of the Pacific Coast League, which is supposed to be much more favorable to those in the batter's box than those on the mound? And what about International League parks?

Well, that's where park factors come in. Park factors do their best to show us how much a certain stadium helps or hurts hitters and pitchers as compared to other environments. Like Ashley Marshall did before the 2014 season, we'll consider runs, home runs and hits, but with more recent data and a couple of new stadiums to consider as well.

Here's the equation for run factors (substituting homers and hits as necessary for their respective factors):

((Runs scored at home + runs allowed at home)/(Home games)) / ((Runs scored on the road + runs allowed on the road)/(Road games))

In simpler terms, take the total runs scored at a given park and divide it by the amount of runs scored by the team when it visits all other parks in its league. A perfect 1.000 ratio tells us that a park is perfectly fair to both hitters and pitchers. Anything above that, it's a hitter's park. Anything below, it's a pitcher's park. 

This is how park factors have shaken out thus far in the International and Pacific Coast Leagues in 2015:

International League - 2015

Team R HR H
Charlotte 1.479 1.665 1.175
Lehigh Valley 1.188 0.883 1.021
Syracuse 1.170 1.580 1.082
Gwinnett 1.044 0.732 1.010
Buffalo 1.026 1.114 0.913
Columbus 1.021 1.025 1.059
Toledo 1.004 0.827 0.961
Indianapolis 0.960 0.566 1.056
Durham 0.956 1.235 0.946
Louisville 0.950 1.050 0.984
Norfolk 0.873 1.271 1.007
Rochester 0.859 0.613 0.978
Pawtucket 0.833 1.200 0.932
Scranton/Wilkes-Barre 0.820 0.742 0.911

Pacific Coast League - 2015

Team R HR H
Albuquerque 1.379 1.421 1.200
Omaha 1.256 1.230 1.059
Colorado Springs 1.234 1.135 1.152
Salt Lake 1.218 1.453 1.107
El Paso 1.190 1.030 1.158
Las Vegas 1.187 1.112 1.133
Round Rock 1.074 1.280 1.027
Fresno 1.036 0.983 0.973
Reno 1.016 0.823 1.072
Oklahoma City 0.934 0.783 1.031
New Orleans 0.862 1.026 0.921
Iowa 0.828 0.563 0.833
Memphis 0.793 1.015 0.946
Tacoma 0.738 0.975 0.804
Nashville 0.713 0.570 0.878
Sacramento 0.708 0.695 0.801

So to answer our question at the top: yes, Matz's first half was all the more impressive given that he pitched primarily in a park where 18 percent more runs have been scored than in a theoretical neutral park. His home-road splits back this up as well. Matz posted a 2.45 ERA in seven outings (44 innings) at home compared to a 1.94 ERA in eight starts (46 1/3 innings) on the road. Indeed, he busted down the door to Queens by performing well in a tough situation 2,500 miles away. 

Before we get into how park factors should help us view other prospects' performances, let's add two more tables -- this time to show how parks have affected play over the last three seasons. This smooths out some of the noise that comes from looking at numbers for a single season. The more data, the better, as the saying goes.

A few notes on this, though: you won't find Nashville in the PCL chart below because the Sounds just opened First Tennessee Park this season. To take data from 2013 and 2014 would combine what we've seen from the new park with Herschel Greer Stadium -- a park that acted differently. That being said, you will see Charlotte's BB&T Ballpark and El Paso's Southwest University Park, but those include asterisks because only two years of data were used since it opened in 2014.

International League - 2013-15

Team R HR H
Charlotte** 1.277 1.669 1.089
Columbus 1.106 1.381 1.045
Louisville 1.089 1.024 1.061
Rochester 1.023 0.952 1.021
Gwinnett 0.998 0.914 1.013
Syracuse 0.990 0.925 1.032
Lehigh Valley 0.989 0.808 0.998
Indianapolis 0.981 0.737 1.042
Buffalo 0.977 0.939 0.940
Durham 0.946 1.329 1.016
Toledo 0.944 0.682 0.989
Scranton/Wilkes-Barre 0.921 0.851 0.985
Norfolk 0.887 0.999 0.915
Pawtucket 0.875 1.333 0.893

Pacific Coast League - 2013-15

Team R HR H
Albuquerque 1.297 1.292 1.173
Reno 1.257 1.158 1.155
Colorado Springs 1.247 0.955 1.153
Salt Lake 1.144 1.148 1.081
Las Vegas 1.131 1.042 1.071
El Paso** 1.111 0.967 1.097
Omaha 1.056 1.264 1.019
Oklahoma City 1.025 0.879 1.045
Round Rock 1.001 1.120 1.004
Iowa 0.938 0.838 0.910
Fresno 0.932 1.021 0.982
Memphis 0.831 0.906 0.911
Tacoma 0.754 0.962 0.821
Sacramento 0.748 0.662 0.843
New Orleans 0.736 0.986 0.865


What this means for how you should view certain prospects

Matt Davidson, third baseman, Charlotte: The No. 9 White Sox prospect was named to the IL All-Star team Thursday because he is tied atop the circuit with 13 homers, and don't get us wrong -- it's tough to hit home runs, generally. It's just considerably easier to do it in Charlotte over the past two years. In fact, 10 of his homers this season have come at BB&T Ballpark, despite playing two fewer games at home than on the road. What's more, his slugging percentage at home is .181 points higher (.500 compared to .319) than it is on the road. Davidson's power is his best tool, but it's just not as elite as his 2015 numbers would suggest.

Adam Duvall, first baseman, Sacramento: On the flip side, be impressed by the No. 17 Giants prospect's production in the PCL. Duvall's 16 homers trail only Jon Singleton's 17 for Fresno, despite playing in Raley Field, which has been the toughest place to hit homers in the PCL by a wide margin. Still, the 26-year-old slugger has hit nine of his 16 homers at home this season. The difference comes out much more in his slash lines at home (.240/.292/.461) versus the road (.284/.329/.527). One can only imagine what kind of power production he'd have if he played his home games at Albuquerque or Omaha.

Justin Nicolino, left-handed pitcher, New Orleans: Nicolino doesn't strike guys out at any great clip (5.2 K/9 this season) and doesn't have the dominant stuff that might wow you in person, but in 13 starts for the Zephyrs, he's put up a 2.87 ERA across 78 1/3 innings. A deeper dive shows the reason why the Marlins' No. 2 prospect has been so good in his first season at Triple-A -- he's made nine of his 13 appearances at pitcher-friendly Zephyr Field and owns a 1.43 ERA in 56 2/3 innings there. In four starts on the road, that ERA vaults up to 6.65 ERA -- thanks to five homers allowed in 21 2/3 innings. Nicolino isn't likely as bad as he's been on the road for the Z's, but he probably isn't as good as he's been at home either.

Stephen Piscotty, outfielder, Memphis: If there are any Cardinals fans worrying why their system's top prospect isn't statistically busting down the door, part of the reason might be AutoZone Park. The Redbirds' home has been a little more fair so far this season, but over the last three seasons, it's definitely skewed toward being a pitcher's park. That's showing up in Piscotty's numbers: a .261/.363/.408 line with three homers in 41 home games compared to a .269/.357/.522 line with seven homers in only 34 road games. The 24-year-old right-handed hitter has never been too much of a power guy, but his splits are encouraging.

Brian Johnson, left-handed pitcher, Pawtucket: We'll point to Johnson here, not necessarily to say you should view his 2.68 ERA any differently, because his home (2.31 ERA) and road splits (3.18) are still both pretty good if slightly assymetrical. What's interesting is that his numbers point out something about McCoy Stadium. Although the park gives up its fair share of homers, it also eats up a lot of hits as shown by its .893 hit factor the past three seasons. Indeed, Johnson is holding opponents to an astoudingly low .160 average in 46 2/3 innings at home, but that number jumps to .278 on the road. 

Other odds & ends

  • In its first season, Nashville's new park has been especially helpful to pitchers. Only Iowa's Principal Park has a lower home run factor. Barry Zito (3.16 ERA at home, 4.63 ERA at road) is just one hurler to benefit this season.
  • You might have looked at the powerful performances of Singleton, Domingo Santana and Carlos Correa at Fresno and thought, "Well, they're just doing well because of the PCL." In fact, the Grizzlies' Chukchansi Park has been one of the fairest PCL parks in recent years. That's just one reason why Correa has made the transition to the Majors so smoothly thus far.
  • It's a good thing Francisco Lindor's game isn't based on power. The top Indians prospect, who went deep 11 times between two levels last season, hit only two homers in 104 at-bats at Columbus' Huntington Park, which has a 1.381 home run factor over the last three seasons. The 21-year-old shortstop will be just fine with his plus glove and adequate bat in the Majors though.

Sam Dykstra is a contributor to Follow and interact with him on Twitter, @SamDykstraMiLB. This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.

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