2016 Park-Factor Update: American League

Last week, we updated our mid-May analysis of park factors based on granular batted-ball data, showing the offense-inflating impact that a hot summer can have, especially in certain parts of the country. This week, let’s take a look at the season-to-date overall and fly-ball park factors for all 30 parks, one league at a time, focusing on some interesting park-specific information.

First, here’s the quick-and-dirty on the method used to calculate these park factors. Through August 21, 106,962 balls were put into play during MLB regular-season contests. They resulted in an overall batting average of .328 and slugging percentage of .537, while fly balls generated a .328 AVG and .895 SLG. Line drives generated a .661 AVG and .872 SLG, and ground balls a .237 AVG and .258 SLG. (Oh, and pop ups have generated a .018 AVG and .028 SLG.) Each BIP type was split into “buckets” separated by 5-mph increments. The top fly-ball bucket begins at 105 mph, and the top liner and grounder buckets begin at 110 mph.

For each ballpark, the actual production derived from that park’s actual BIP mix was compared to the projected production, assuming that each BIP bucket generated MLB average production for that BIP type/exit-speed combination. Convert everything to run values, and voila, park factors, both overall and by BIP type.

The table below contains the actual and projected production for all BIP (left columns) and for fly balls only (right) in all 15 AL ballparks:

Overall & Fly Ball Park Factor Data Thru 8/21/2016
BOS 0.355 0.578 0.337 0.556 109.8 112.0 0.393 1.015 0.335 0.924 126.9
BAL 0.340 0.570 0.331 0.547 107.1 101.6 0.344 0.965 0.343 0.938 103.8
TEX 0.342 0.563 0.333 0.538 107.0 104.6 0.352 0.962 0.334 0.889 115.0
CWS 0.326 0.534 0.326 0.506 105.5 103.0 0.303 0.845 0.301 0.780 110.8
NYY 0.320 0.547 0.320 0.521 105.2 111.8 0.340 0.983 0.313 0.849 127.7
CLE 0.343 0.577 0.340 0.558 104.3 101.2 0.359 0.968 0.328 0.888 119.3
HOU 0.325 0.537 0.328 0.522 102.0 115.4 0.342 0.928 0.322 0.858 115.3
MIN 0.341 0.555 0.334 0.556 101.8 100.4 0.355 0.952 0.334 0.947 105.5
KC 0.336 0.516 0.330 0.537 98.2 98.5 0.295 0.759 0.332 0.902 74.0
SEA 0.324 0.550 0.331 0.557 96.7 96.7 0.334 0.939 0.341 0.946 97.5
LAA 0.320 0.510 0.324 0.535 94.4 94.2 0.319 0.846 0.326 0.890 92.4
TB 0.317 0.540 0.327 0.558 93.7 95.3 0.291 0.867 0.332 0.929 83.1
TOR 0.328 0.559 0.339 0.579 93.3 97.3 0.343 0.987 0.360 1.055 88.7
DET 0.333 0.551 0.337 0.587 92.7 97.0 0.310 0.890 0.362 1.039 73.4
OAK 0.308 0.485 0.325 0.533 86.5 85.8 0.297 0.785 0.327 0.901 78.2
AL AVG 0.331 0.545 0.331 0.546 99.9 101.0 0.332 0.913 0.333 0.916 100.8

The table above is presented in descending 2016 Park Factor order. Fly-ball park factors for all parks are presented, as they are the primary driver of overall park factors. As you see, the eight stadia with fly-ball park factors over 100 have overall park factors over 100, and the seven with fly-ball park factors under 100 have overall park factors under 100, with the same stratification of overall park factors also applicable in 2015.

Some key MLB-wide data to keep in mind as we take a park-by-park look at some underlying drivers that made them hitter or pitcher-friendly: 82.9% of all fly balls (20-50 degree launch angles) hit at 105 mph or higher had gone over the wall through 8/21. At 100-105 mph, 48.0% of flies were homers, with the percentage dropping to 15.5% between 95-100 mph and 3.1% between 90-95 mph.

Only 176 line-drive (between 5-20 degree launch angle) homers, or just under six per park, were hit through 8/21. Of liners hit at 110 MPH or higher, 11.1% were homers. The mark dropped to 3.7% between 105-110 mph and 0.6% between 100-105 mph.

Without further ado, here are some defining characteristics of the 15 AL parks through 8/21:

While somewhat hitter-friendly, Camden Yards isn’t quite the launching pad many believe it to be. You see, the O’s (and their opponents, for that matter), hit the ball pretty hard. It does have a 117 home-run PF to date, and has easily outpaced the MLB average for homers on 100-105 mph fly balls (56.0%). You can hit a liner out of this place: 19 liner homers have been hit here, including 25.0% of those hit at 110-plus and 9.5% of the 105-110 mph variety.

Fenway is certainly unique. As usual, the Monster is inflating two-base hits, with a 119 doubles PF to date. Fly balls at 90-95 mph are dead outs most of the time, going for a cumulative .122 AVG-.307 SLG in all parks, with a 6.9% doubles rate to date this season. In Boston, hitters are batting .259 AVG-.524 SLG on them, with a 14.5% doubles rate. This is the only park in the game that routinely inflates offense while deflating homer totals.

US Cellular has developed a fairly distinct profile over the years: it inflates homers, but isn’t as hitter-friendly overall as one might expect, as it deflates all other types of hits. It has a 128 homer PF thus far this season, as 56.2% of 100-105 mph fly balls have gone over the wall. It’s also among the easiest parks in which to hit a line drive over the wall: 12 liners homers have been hit altogether, with a 10.1% homer rate from 105-110 mph.

As indicated in last week’s piece, offense exploded in the Great Lakes region this summer, especially in Cleveland and Pittsburgh. The homer rate on 100-105 mph (53.8%) and 95-100 mph (18.8%) fly balls exceeded the MLB average, due in part to the hot summer. In addition, Progressive Field’s doubles PF of 115 to date gives Fenway a run for its money.

Comerica Park’s stinginess makes Miguel Cabrera’s long-term greatness stand out even more. While it does inflate singles moreso than any other AL park (107 1B PF), it has throttled doubles (78 PF) and homers (85 PF) this season. Only 69.1% of 105-plus mph and 38.9% of 100-105 mph flies had cleared the fence through 8/21.

Minute Maid Park both giveth and taketh away. The large middle third of the field can suck up some 100-105 mph fly balls that would leave most parks (43.8% homer rate), while the park has yielded nine line drive homers, including a 2.7% homer rate on 100-105 mph liners. It will also yield some three-base hits, with a 145 triples PF to date this season.

Kansas City
A well-established pitchers’ park, Kaufmann Stadium has an 80 HR PF this season, and only its singles PF is above 100. Only 39.4% of 100-105 and 10.1% of 95-100 mph fly balls have left the building thus far.

Los Angeles of Anaheim
If you hit a fly ball over 100 mph, you have about an MLB average chance to ride it out of this yard. Angel Stadium gives away no cheapies, however: only 10.9% of 95-100 mph homers have left the building to date, driving its fairly typical 88 2B and 95 HR PF through 8/21.

Target Field is not an easy home-run park; only 38.7% of 100-105 and 13.1% of 95-100 mph fly balls through 8/21 cleared the wall. It does qualify as a slightly hitter-friendly park overall thanks to its penchant for giving up doubles (109 2B PF this far in 2016).

New York
Neither the Yankees nor their opponents have hit the ball very hard this season, but the usage of granular data to create park factors in this manner makes it clear that Yankee Stadium is still a hitters’ park. It’s all about the homers here, as singles, doubles and triples totals are deflated. The actual homer rates for 100-105 mph (55.3%), 95-100 mph (26.2%) — and even 90-95 mph (10.2%) — fly balls far outpace MLB norms. There are plenty of cheapies to be had down both lines.

O.Co Coliseum is the only park in the AL that has deflated singles, doubles, triples and homers this season. Only 40.3% of 100-105 mph and 9.5% of 95-100 mph fly balls have cleared the wall there this season.

A few years back, the fences were moved in fairly substantially at Safeco Field in an attempt to make the formerly extreme pitchers’ park more neutral. Mission accomplished. The homer rates on 100-105 mph (48.7%) and 95-100 mph (14.9%) fly balls are almost exactly league average. Interestingly, an underrated aspect of the park’s new configuration is the lowering of the left-field fence. Twelve line-drive homers have been hit this season, with unusually high homer rates on 105-110 mph (5.9%) and 100-105 mph liners (3.3%).

Tampa Bay
Tropicana Field is, on balance, a pitchers’ park, though it will give up some homers. Its singles, doubles and triples PFs are under 100 this season, with the HR PF narrowly above average at 101.

A tried-and-true hitters’ park due to its susceptibility to the home run. Its homer rates on 100-105 mph (56.4%) and 95-100 mph (18.5%) fly balls are both well above MLB average.

Rogers Centre has a largely undeserved reputation as a hitters’ park. Yes, the park gives up plenty of homers, but that’s largely due to the cast of characters who play there. The hardest fly balls and the second-hardest set of BIP altogether have been hit in Toronto this season. The homer rates on 100-105 mph (45.4%) and 95-100 mph (14.1%) fly balls have both been unremarkable.

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I still hate that they ruined Safeco Field. I basically stopped being a Mariners fan when that happened,

I loved the old Safeco dimensions. Combined with that cold damp wind in from Puget Sound, that place was death to right-handed hitters.


Yes. Because nothing’s more entertaining than watching a HOF talent like Adrian Beltre hit 110 MPH warning-track flyballs.


Indeed, Ardian Beltre may never get into the HoF solely because of what Safeco did to his numbers over the time he played there.

(BTW, as subtle sarcasm goes this post is itself HoF-worthy)