The Milwaukee Brewers are currently 23-16 and are coming off consecutive sweeps of the New York Mets and Washington Nationals. As of writing these words, they sit in second place in the National League Central behind the Chicago Cubs. The Brewers have one more win than their rivals, but also three more losses, leaving them trailing by a game. All of this relatively good news for the Brewers and their fans.

But if you pull away the weeds and look closer into the grass, you’ll notice a substantial difference between the teams. The Brewers have a +2 run differential. The Cubs have a +57 run differential. Run differential is very telling and relatively predictive when it comes to record, so the simplest way to put it is that the Brewers probably haven’t been as good as their record says they are, while the Cubs most likely have been better. It’s not the offense that should be blamed for Milwaukee’s mediocre run differential, though. As of May 9, the Brewers have scored the sixth-most runs in baseball, just 10 home-plate touches behind the Cubs, The offense — also known as Christian Yelich — is carrying its fair share of the load. That’s clearly not the issue.

It’s the starting pitching — the group in which almost every analyst with a microphone criticized before the season — that’s been more of a problem than the way Game of Thrones handled Ghost.

Before I go any further, you should know that Milwaukee’s starting pitching staff has turned a corner in the past week or so. It’s still not gold-star worthy, but Zach Davies and Brandon Woodruff have been dealing like aces, and Gio Gonzalez‘s return has been excellent. That deserves to be recognized. But we need to talk about more than just a week’s worth of performances. Small sample sizes rarely mean anything, unless you’re Skip Bayless and you need a hot take.

So here is how the Brewers starting rotation ranks in key categories for the season (as of 5/7).

Milwaukee’s rotation has been ugly thus far, and frankly, it can’t get much worse, unless, you know, you’re the Orioles, who give up more dongs than Bryce Harper‘s dad.

But why have they been so pitiful? With the swing-and-miss talents of Corbin Burnes, Freddy Peralta and Woodruff, they should be significantly better, right? They should be, but they’re not, and a lot of their misfortune can be blamed on fastballs.

Let’s start by breaking down each starter (minimum 10 IP) by their fastball usage.

According to Baseball Savant, fastballs are classified as four-seamers, two-seamers, cutters and sinkers, and the Brewers — as my chart so neatly illustrates throw them quite a bit. Only 10 teams have starters who throw them at a higher rate, yet no team is being punished more than the Brewers.

The below table includes every player who’s made a start for their respective teams in 2019, not just those who fall under the 10-inning minimum like the above table.

Hitters feast on fastballs more than any other pitch. As a league this season, hitters have hit for a .352 wOBA on pitches classified as fastballs, while those same hitters have a .272 wOBA versus breaking pitches. Due to the nature of baseball, it’s expected that teams will allow a high fastball wOBA, but the Brewers happen to be on the lofty end of the spectrum.

Luckily for us, Baseball Savant has statistics dating back to 2008, meaning we’re able to compare seasons over the past 12 years. The Brewers are allowing a .419 wOBA when their starters throw a fastball, and if the season ended today, Milwaukee would hold the record for the highest wOBA allowed on fastballs during that period. No other starting rotation since 2008 has been destroyed on fastballs as much as the Brewers, which is just laughably insane, but also likely unsustainable.

A lot of their problems are due to the long ball, as 27 of the rotation’s 36 home runs they’ve allowed have been via the fastball. Burnes and Peralta have been the biggest culprits of fastball harm. Burnes seems like he gets lit up every time he throws a fastball (10 home runs allowed), and since Peralta basically only throws fastballs, it’s no surprise hitters have conquered it. Location, as you might’ve guessed, has been the biggest enemy, not only for those two, but the rotation as a whole.

When their starters throw a fastball, they’re putting them right down the middle at an alarming rate, and opposing hitters are taking advantage of those mistakes, as they should since they’re major league hitters. Here are the pitch locations for every home run they’ve allowed.

Nearly every single one of those pitches has been a mistake in location. Leaving a fastball anywhere in the middle of the zone is generally not a good thing. Groundbreaking, I know.

But this is why the Brewers rotation has been swimming in the bottom of the league. They’re throwing too many fastballs and are getting murdered for it I don’t know if Milwaukee’s pitching coach Chris Hook should shoulder the blame for this, but pitch sequencing has definitely been a big issue, and it needs to change soon if the Brewers want to compete in their tough-as-nails division. Yelich and the rest of the offense won’t be able to carry the hurlers forever.