How much did the umpires help/hurt the Giants in 2021?

*All credit for the idea and original Statcast search goes to SnowLeopard, from this comment

Picture this. It’s the bottom of the ninth, two outs. Game 5 of the NLDS against your most storied rival. You’re down a run, tying run is on first. Two outs. Two strikes. But you’ve got 20-homer power and a hit in this game already. No, it’s not a sure thing. Nothing in baseball ever is. But the bat’s in your hands. That’s the beauty of the game, really: you make your own fate.

Wind up. Deliver. Throw. Slider, down and away. 86mph. Out of his hand it looks like a fastball, so you start your motion. But recognize quickly that it’s a breaking pitch out of the zone. You steady your hand. You stop your swing. Ready to rest up, prepare for the next pitch. You’ll be faster on the recognition next time, but still. Given that you had less than a blink to hold yourself up, you feel you did pretty well.

But wait. Something’s wrong. The pitcher is celebrating. So is the catcher, who’s gotten out of his squat to sprint to the mound. Sometime in that brief moment of reprieve, the umpire has ruled you went around. Even though you didn’t break the plane of the plate. Your season is over on an erroneous call that cannot be reviewed.

Obviously, this happened. In fact, things like this happen all the time. Umpires are far from perfect. A 2018 article out of Boston University found that MLB umpires missed 34,294 calls over the course of the 2018 season, or roughly 1.6 incorrect calls an inning. Sometimes these calls aren’t too bad: a borderline pitch gets called a ball, or a strike, and the count goes to 0-1 or 1-0. While it can change the outcome of an at-bat, it’s not as blatantly obvious as game-ending calls that change the narrative in an instant.

But there are some truly egregious mistakes, ones that do change outcomes. That’s what we’re going to take a look at today: two cases—

1. 2-strike count, ball is called a strike, batter strikes out unfairly (umpire-gifted out)
2. 3-ball count, strike is called a ball, batter walks unfairly (umpire-gifted baserunner)

The idea here is that the first scenario is bad if your team is batting, and good if your team is pitching. The second scenario is the inverse: good if your team is batting, and bad if your team is pitching. By understanding where the Giants rank along these dimensions, we can get a sense of how much the umpires helped/hurt the team over the course of the season.

Scenario 1 (incorrect strike threes): Team batting

Source: Statcast

There’s nothing worse than a called third strike that should’ve been a ball. To limit this, batters will often try and protect with two strikes: they’ll take emergency swings at balls they wouldn’t offer at in the beginning of an at-bat. But some balls truly are far enough outside the zone that swinging at them brings the risk of swinging through them and striking out anyways. So frequently there is no better choice than to take a ball you’re certain is a ball. And when the bat is taken out of your hands by the umpire, it can often be one of the most frustrating plays in a baseball games, for both fans and players alike.

In 2021, no team in the big leagues had more of these incorrectly called third strikes than the Giants. They were first in baseball with 92 at-bats ending in incorrectly called third strikes. (You can determine what should be called a ball by using Statcast’s “Gameday” zone in search, and by filtering for pitches that were called strikes even in these non-strike zones, that’s how you can get the answer). There were 1,975 at-bats that ended in this manner, and the Giants were responsible for 4.7% of them. This wasn't something that improved by being at home, either: 47 of those 92 incorrect calls (51.0%) occurred at Oracle Park.

You remember some of these calls, probably. You might’ve been shaking your fist at the TV, or listening to Miller’s sound of exasperation, or watching the Gameday zone on your MLB App update in real time with a sound of disbelief. Even if you don’t remember the situation exactly, you remember the frustration and the anger. Soak in that Flores missed call. Multiply it by 92. That’s how many times you felt like that over the course of a season.

The only small saving grace is that the team right on the heels of the Giants for this unfortunate stat are the Los Angeles Dodgers, with 89 missed strike three calls of their own. Small victories?

Scenario 1 (incorrect strike threes): Team pitching

Source: Statcast

At least, if the umpires are going to screw you in this direction, they might as well help you in the other. That has to be the case, right? Maybe it’s not that the Giants were unlucky. Maybe it’s that they happened to get umpires with weirdly large zones. But at least the Giants’ pitchers should be benefitting from that too, right?

Not quite. Giants pitchers did get 69 strike threes called that should’ve been balls, but that ranked just 13th in the big leagues. The pitching staff that stole the most strikeouts was the Philadelphia Phillies, who had 100 calls made in their favor in this manner.

The Giants had a net –23 at-bats that were designed to help them (the number of strikeouts gifted to pitchers minus the number of strikeouts unfairly given to batters). That was the second-worst mark in the big leagues, behind only the Dodgers, who had a net –29. The Phillies led the pack at a net +52 strikeouts gifted by umpires.

Scenario 2 (incorrect ball fours): Team batting

Source: Statcast

The flipside to an unfair strikeout is an unfair walk, which helps the batter. We all know the scenario: a wild pitcher, who is unable to throw strikes, gets to a three-ball count on a hitter and even though their next pitch would probably have been called a strike if they’d had their command, the ump deigns it a ball, anyways. Kruk and Kuip sometimes refer to this as the outcome of a pitcher needing to “prove” he can throw strikes: if you’re too wild, you get less leeway from the umpires.

Unfair walks can help your team, especially if they lead off innings or occur in other situations where a man on base is a prime asset. Given how much the Giants were screwed on strike threes, it’d only be right to assume they were paid back in kind by getting lots of unfair walks.

...kind of. The Giants ranked 14th in baseball in unfair free passes, with 25 over the course of the season. This trailed the leader of the pack, the Dodgers, who had 32 free passes gifted to them, but the differences are much smaller than they were with the strike threes.

Scenario 2 (incorrect ball fours): Team pitching

Source: Statcast

The final scenario to consider is when your team is pitching and it’s your guy who’s effectively wild (or just wild) on the mound. You’re hoping that the ball that grazed the outside edge of the strike zone will go in your favor: the other team is not.

Finally, the Giants rank somewhere positive: they were 29th in baseball with 15 of these calls not going their way, trailing far behind the Rockies, who led the pack with 33 missed ball fours that should’ve been strikes. This could be a testament to the strength of the Giants pitching staff: overall, 50.9% of their pitches were within the Gameday strike zone, a mark that tied for 1st in MLB (with the Dodgers). In general, the ball was going where the Giants pitchers wanted it to go. The Giants pitching staff had by far the lowest BB/9 (walks per nine innings) in the majors in 2021: 2.57. The next closest was the Tampa Bay Rays, at 2.70. So the improved command from the Giants staff helped keep this stat in the Giants’ favor.

Overall

Overall, the Giants had net 13 at-bats where the umpires unfairly decided which way it would go, without an equivalent mistake in the other direction. (I calculated this by adding up the “helpful” at-bats: batting ball fours plus pitching strike threes, and then subtracting the “unhelpful” at-bats: batting strike threes plus pitching ball fours). This number ranked 26th in baseball, meaning the umps were more helpful to 25 other teams. The Phillies led the pack with net +38 calls in their favor, while the Dodgers were the worst off, with net -22 calls in their favor.

Feel free to play around with the data and net data here, if you’d like.

Verdict

The Giants weren’t quite the worst-off team in baseball, but the umpires certainly did not help them in any meaningful manner, and frequently hurt them. I’m sure players like Brandon Belt (who had 17 incorrectly called strike threes, most in baseball) can’t wait for the implementation of roboumps.