Did Yankee Stadium hurt the Yankees in 2015?

A week after making his Major League debut, Yankee first baseman and beloved prospect Greg Bird hit his first big league home run, followed by his second two innings later. Both came off of Twins pitcher Ervin Santana, who was not at all pleased after surrendering the two homers. In fact, rather than blaming himself and his poor pitching skills (he had a 4.00 ERA and 4.17 FIP in 2015, which was one of his better career years), he immediately placed the blame on Yankee Stadium. Referring specifically the second home run Bird hit, Santana said, "I know, probably in another park that's a double. But here, it's a joke."

Unfortunately for Santana, both of Bird's home runs that night were far from funny, the first traveling 383 feet and into the upper deck.

And the second one, the one Santana blamed Yankee Stadium for? That one ultimately traveled 418 feet. So much for the Yankee Stadium excuse, Ervin. Better luck next time.

Despite being wrong in this case, Ervin Santana does have some semblance of a point: Yankee Stadium is definitely and inarguably a hitter-friendly ballpark, especially in terms of home runs. From 2010 to 2012, Yankee Stadium ranked as the sixth most hitter-friendly stadium and allowed the fifth most home runs in baseball. In 2015 it ranked fourth in park factors in terms of home runs and in total yielded 219 home runs, which averages out to 2.70 home runs per game played (second only to Camden Yards' 222 home runs and 2.96 HR/game). Of the 219 home runs hit at Yankee Stadium in 2015, 39 (18%) would have only been home runs in less than five stadiums, and 26 (12%) would not have been home runs in any other ballpark in the Major Leagues. We will refer to those 26 home runs as "Yankee Stadium specials."

This begs the question, who benefitted most from Yankee Stadium's propensity for home runs? To start, the dimensions of the stadium are as follows: 318 feet in left, 399 feet in left center, 408 feet in center, 385 feet in right center, and 314 feet in right. The following picture from the Yankees' website shows the true shape of the ballpark well.

Due to the "short porch" in right, lefty pull-hitters have the greatest home run advantage. This speaks to the makeup of the projected 2016 opening day Yankee lineup, as switch-hitters Mark Teixeira, Carlos Beltran, and Chase Headley can hit left-handed in addition to Didi Gregorius, Brian McCann, Jacoby Ellsbury, and Brett Gardner. Only Alex Rodriguez and Starlin Castro are right-handed hitters. The Yankees signed Dustin Ackley in large part because they thought his left-handed swing would fit their stadium well.

Specifically, of the Yankees' 2015 hitters, Yankee Stadium gave the most gifts to slugger Stephen Drew. Of his nine Yankee Stadium home runs, only five would have gone out in any other ballpark. Here's an example of a Drew Yankee Stadium home run:

That was clearly a cheapie. According to ESPN Hit Tracker, that ball is not a home run in any stadium, including Yankee Stadium. It probably shouldn't count for anything. Other than Drew, McCann and A-Rod were gifted the most Yankee Stadium home runs, each hitting three apiece.

Although the Yankees were gifted several home runs at the plate, the Yankees did not always benefit from their stadium's dimensions in 2015. A few Yankee pitchers struggled at home, namely Masahiro Tanaka, Ivan Nova, CC Sabathia, Michael Pineda, and reliever Chasen Shreve. Their home versus away splits are shown in the table below.

Clearly Tanaka cannot stop giving up the long ball at Yankee Stadium, but none of the home runs he allowed in 2015 were Yankee Stadium specials. Nova had a pretty bad season in general after his second-half return from Tommy John surgery, so we won't delve any deeper into his struggles. Sabathia gave up a lot of home runs at Yankee Stadium, but he kind of did that wherever he pitched in 2015. It's his thing now. Shreve also greatly struggled at home in terms of both ERA and home runs (yes, those are related), but he did not allow any Yankee Stadium specials.

Of Yankee pitchers, only Michael Pineda significantly struggled more at home than away due to "Yankee Stadium special" home runs. He gave up four of them this past season (one to Ben Revere!), which is partially responsible for his inflated 2015 4.37 ERA compared to his 3.34 FIP and 2.95 xFIP, and is definitely a reason for his 1.61 HR/9 at home versus his 0.63 HR/9 away (!).

Nathan Eovaldi joins Pineda as a Yankee pitcher who suffered the fates of Yankee Stadium most in 2015, as he allowed three Yankee Stadium specials. However, home runs are not a major problem for him (but somehow singles are), and he actually pitched better at home than away in 2015. Two of his Yankee Stadium specials shouldn't have even been home runs at Yankee Stadium.

So, did Yankee Stadium's size hurt the Yankees more than it aided their offense in 2015? Hard to say. Of the 26 Yankee Stadium specials hit last year, 15 of them were hit by the Yankees and they were responsible for 22 runs. On the other hand, 11 were hit by opposing hitters, which combined for 17 runs total. Of the non-Yankee home runs, only two were not solo home runs. In the end, it's not much of an advantage if Yankee pitchers can't keep the ball in the park.