Has the home run surge hurt the Giants?

Earlier this week, I wrote about how home runs are once again on the rise. We thought there couldn’t possibly be any more dingers in a season and then a salesman walked over, slapped the regular season schedule, and said, “This baby can fit so many dingers in it.”

We got a taste of what it must be like for a team to play in a normal park when the Giants hit five home runs in their two-game series in Toronto. The ball is flying, but it’s something the Giants don’t get to partake in with the extreme pitcher’s park they call home (or at least until their agreement runs its course and they change the name to Home Presented by Camping World).

Home runs have been on the rise since the second half of 2015 when a different ball was introduced. Since then, the Giants are 273-311. The Giants have been an okay team at home. Grant has already shown that Oracle Park has been unaffected by the rise in home runs. Over the last two years, when home runs have been at their highest, they’ve been especially bad on the road. Their record on the road in 2017 and 2018 is 57-105. At home, it was 80-82.

Because of their home park, the Giants have had to get creative with their roster construction. Sluggers with some agency about where they want to play don’t want to come to San Francisco. The Giants had a deal in place to trade for Giancarlo Stanton, but he opted to go to the Yankees instead. They also offered Bryce Harper a $311 million contract which he turned down to go to Philadelphia. While the park wasn’t the deciding factor in both cases, it was a factor.

Instead of bringing beef lords to San Francisco, the Giants have had to settle for guys like Kevin Pillar and Evan Longoria, who might have OBPs under .300, but will catch anything hit near them. The Giants have been successful with pitching and defense in the past, but is pitching and defense as effective when fly balls that used to be outs sail over the fence where no one can catch them?

I’ve looked at the Giants HR/FB rates going back to 2011. That includes the four years before the ball change and the four years after. I’ve split it up by home and road to see what kind of difference Oracle Park has made.

I’ve also included HR/FB%+, which is FanGraphs’ new plus stats. It works the same as OPS+, wRC+, and DRC+. A HR/FB%+ of 100 is exactly league average. Every point above 100 means that a hitter or team is one percent higher than league average. Every point below 100 means they are one percent lower than league average. Values below 100 are good for pitchers. Values above 100 are good for hitters. For instance, the 2017 Giants offense had a HR/FB%+ of 63, so they were 37 percent worse than league average.

As far as I can tell, FanGraphs doesn’t have a way to split the plus stats by at home or on the road, so the HR/FB%+ numbers are home and away.

First, the hitters.

And now the pitchers.

On both sides of the ball, HR/FB rates rose both home and away by roughly equal amounts. HR/FB rates were much higher on the road which isn’t surprising. Giants pitchers saw the largest increase of HR/FB rates on the road following the juiced ball. In the four years prior, Giants pitchers averaged a 10.3 HR/FB rate, and in the four years after, that rose to 13.4. Hitters didn’t see that same sort of boost, so it looks like the Giants were disadvantaged on the road. However, the HR/FB%+ didn’t budge.

The rises in HR/FB rates were mostly consistent with what the league was doing. Even with a three percent increase for pitchers on the road, their HR/FB rate was better compared to league average.

Relative to the league, the Giants are hitting and allowing the same number of homers per fly ball as they were before the ball was juiced. But, the home run surge has had more effects that just seeing the ball leave the yard. Because homers are easier to come by, teams are more reliant on homers for scoring.

Baseball Prospectus’s Guillen Number is the percentage of runs that a team scores via home run. Between 2011 and 2014, the average team scored 34.9 percent of their runs by hitting the ball over the fence. Between 2015 and 2018, that number rose to 39.9. Across the board, the average team saw their Guillen number rise by five percent. The Giants, however, only saw it rise by 28.3 to 30.2. There were some teams that saw smaller gains and, in the case of the Braves who moved stadiums, a significant drop. 30.2 is the lowest mark since the ball was juiced.

A high Guillen Number does not necessarily mean that a team has a good offense. The Orioles had the fifth-highest Guillen number last year and their non-pitcher wRC+ was lower than the Giants. But, being so far behind a league-wide trend has to mean something, right?

Teams are more reliant on the long ball because strikeouts keep going up and singles are going away. The Giants are more dependent on driving in runners without a home run so it might be that the increased strikeouts are disproportionately hamstringing the Giants, but that doesn’t really hold up. For one thing, strikeouts would rise regardless. For another, the Giants were slightly better at avoiding strikeouts and hitting singles with runners in scoring position post-juicing.

It’s tempting to think that the Giants struggles are tied to the change in the ball. When I started writing this, I was ready to blow the lid off this conspiracy to kill Even Year Magic, but now I’m less convinced that the home run surge is responsible for the Giants’ woes. I’m sure that there’s something I haven’t considered, but the answer is probably more obvious: The Giants don’t score runs because they don’t get on base.