Brandon Belt Rightly Resists the Revolution

On Wednesday night, Brandon Belt came to the plate six times. He drew four walks, struck out once, and put one ball in play, a single in the 11th that drove in a run. Of course, the combination of all those walks and the relative lack of homers sometimes leads to spurious criticisms not unlike those leveled at Joey Votto. While most understand that Votto is a great hitter and many understand that what Belt does is good, Belt’s reputation likely suffers more than Votto’s for a few reasons.

1. He’s not as good as Joey Votto.
2. He hits relatively few homers for a first baseman.

As to that first point, there’s no shame in failing to rival Joey Votto. As to the second, it really is hard to overstate the effects of Belt’s home park. Despite what Barry Bonds might have led everyone to believe, it’s incredibly difficult to hit homers in San Francisco. Despite what Barry Bonds might have led everyone to believe, it’s even more incredibly difficult for lefties to homer there.

Brandon Belt isn’t without power. He has posted ISOs well above league average throughout his career. Since the beginning of 2015, his .226 ISO on the road is 23rd best in baseball among the 160 players who’ve recorded at least 500 away plate appearances. He’s within 10 points of Joey Votto; he’s right behind Josh Donaldson, Brian Dozier, and Daniel Murphy; and he’s just ahead of Miguel Cabrera and Jose Bautista. In 580 away plate appearances since the beginning of 2015 — roughly a season’s worth of playing time- – Belt has 28 home runs, having hit them at a greater rate than Kris Bryant and Paul Goldschmidt. His numbers are good in high-leverage and low-leverage situations. He’s good with runners on and the bases empty. He’s consistent, too, as the chart showing his 100-game rolling ISO shows.

He’s also never hit more than 18 homers in a season and doesn’t seem likely to do so this year. In addition, look at Belt’s ISO compared to first basemen as a whole the last few seasons.

Belt’s power figures have remained roughly the same, even as the league around him has boosted its power. Belt’s overall offensive line has remained just as good relative to the rest of the league, however, thanks to an increase in walks. There has been much theorizing about the increase in offense over the last few years. One of the more prominent theories concerns the effects of ever higher launch angles, as hitters try to boost their power numbers by hitting the ball in the air more often.

Would that work for Belt? Probably not, actually. Not because he would lose something else as a hitter, but because it wouldn’t necessarily help him in San Francisco. Belt actually did hit more fly balls last season; his power numbers barely moved, though. As a lefty hitter hitting in a park that suppresses power — particularly for left-handed hitters — it’s not really clear that maximizing launch angle would provide Belt with much benefit.

It’s tough to show exactly how much worse it is for lefties to hit in San Francisco than in other parks, but it is probably best to start with park factor. The graph below shows the park factor for home runs by left-handed hitters. The higher the number, the easier it is to hit them out of the ballpark.

San Francisco is last by quite a bit. It’s a good park for triples, but those don’t really happen often enough to make a huge difference. And it’s still in the bottom third for doubles.

Going beyond park factor, we can see just how this problem plays out using Statcast. Baseball Savant now carries xwOBA as part of the available metrics. xwOBA utilizes exit velocity and launch angle to determine what the wOBA on any given play likely would have been. We can isolate by left-handed hitters and venue to get a better sense of what happens when lefties hit the ball in each park.

For this search, we will look at Barrels — that is, batted balls with the sort of launch angle and exit velocity that typically produces a batting average of at least .500 and slugging percentage of at least 1.500. Since the beginning of 2015, every park has seen around 200 barreled balls from left-handed batters. The average wOBA on these balls is 1.411 and the expected wOBA on these balls is 71 points lower, so across the league, lefties generally exceed their expected wOBA when they barrel a ball. The graph below shows the difference between expected wOBA and actual wOBA since 2015, with a higher number meaning batted balls are underperforming what we might expect.

In the smaller parks in Milwaukee and Cincinnati, the thin air of Colorado, and the notoriously short right field of Yankee Stadium, lefty hitters outperform their expected wOBA. Detroit is an average park for left-handers hitting homers, but is considerably more difficult for doubles. Kansas City is a hard park in which to homer, and the club’s defense might play a role there, as well. San Francisco is one of just three parks where barreled balls produce considerably worse results for lefties compared to the rest of baseball. The disparity is there for Giants hitters and their opponents.

To provide another perspective on the data above — and remove defense from the equation entirely — we can take all of the barreled balls by park and look at the percentage of those batted balls that go for homers. League average is 55% for left-handed batters.

It’s hard for lefties to hit homers in San Francisco. When a hitter barrels a ball in Yankee Stadium or Dodger Stadium, it goes out of the park two out of every three times. When it happens in San Francisco, it’s a homer roughly half as often. This is true both for the Giants and their opponents. Brandon Belt doesn’t hit a lot of homers because San Francisco doesn’t let him. It doesn’t allow any lefty — Barry Bonds excluded — to hit a lot of homers.

Brandon Belt is a good hitter with power. His walks have allowed him to keep pace with the rest of the league offensively, as increasing his power numbers would likely be a fool’s errand. Brandon Belt doesn’t hit for a high average or hit a lot of homers. He’s not fast on the bases. He doesn’t need to do any of that, however, to be very good. He walks a lot and he hits for power, even if the ball doesn’t leave the yard. That’s all he needs to do to be one of the top-25 hitters in baseball.