By Cam Ellis

It's no secret that the Nationals can pitch a little. Besides having MLB's lowest ERA, the Nats boast a top-10 mark in batting average against, strikeouts, and quality starts. They're probably in the upper echelon of a variety of additional pitching stats, but you get the point. A bigger question mark than usual heading into the season, the Nats have ridden bounce back performances from Tanner Roark and Gio Gonzalez, relied on the steady all-star talent of Stephen Strasburg and Max Scherzer, and gotten a surprising lift from Joe Ross on the way to a franchise-best start. 

What's made their pitchers so tough thus far? What pitches work for them and which ones should they stay away from? Using a handful of different statistics, this article looks to explain what pitch is each starters strongest and most effective. One of the best ways to get a singular representation of a pitches value is using FanGraphs' Pitch Type Linear Weight value, which is explained in full here. Like any lone baseball stat, it doesn't tell the whole story; what it does is help give an understandable value to each pitch and help shed light on how valuable it is to the pitcher. Which pitch is most valuable to which pitcher? Let's take a look. 

Max Scherzer

 

Best Pitch: Slider

Scherzer's case is tricky because the question of sample size comes into play. As you'll see above, the numbers suggest his cutter is his most effective pitch - a cutter he's only thrown three times all year. His slider generates the most swings out of the strike zone (O-Swing%), the most amount of swinging striks (SwStr%), and the least amount of contact (Contact%) in general. 

The chart above shows the batting average against each of his pitches. Considering his three most common pitches thrown are his fastball, slider, and change up, and his slider's BAA is the lowest of any three of those, it stands to reason that that's his best pitch. 

Once again, we're leaving Scherzer's cutter out of any debate because he's only thrown three all year. With that in mind, his slider takes over as the most swung at pitch, evident by it's 19.35 wiff percentage. Scherzer leans heavily on his four-seamer, but when he needs a go-to out, the numbers say he goes to his slider. 

Stephen Strasburg

Best pitch: Change up

This one's no secret. Strasburg's change up has always been lethal, and the numbers show it plenty of love. A 3.1 pVAL is his best by far, and the Swing and Contact numbers back up the claim. What's especially important here is that there's a fair sample size for all, minus the two-seam. Through four starts, Strasburg has evenly distributed his breaking balls, but the change up has been his bread and butter. 

 

As if you needed any more convincing: a 0.00 batting average against his change up. 

Brooks Baseball lists Strasburg's two-seamer as a sinker because of the similar movement on each pitch. No matter - the change up still takes the cake with a 22.92 wiff percentage. 

Gio Gonzalez

Best pitch: Changeup, barely 

This is the closest one yet. Interestingly enough, Gonzalez's change has much better Swing percentage numbers, while his curve has better Contact percentages. pVAL gives the slight edge to the change up, that's probably has something to do with the fact that he's thrown more change ups than curves. 

Still, it's neck and neck. The change garners a .071 batting average against while the curve generates a .091 baa. It's splitting hairs, but hey, that's what analytics is all about! 

These two graphs echo what the FanGraphs board said: it's really six one, half-dozen the other with Gonzalez. It's not groundbreaking, but interesting to see nonetheless. A case could easily be made for Gio's curve, but for now we'll say that his go-to pitch his the changeup. 

Tanner Roark

 

Best pitch: Changeup, by a mile

It's pretty terrifying when your number four starter is capable of a 15-strikeout game like Roark's last outing. His numbers across the board are pretty pedestrian - except for his changeup. Both his pVAL and his pVAL/C (the latter adjusted to a value per 100 pitches) on the change dwarf any of his other pitches, and the Swing and Contact numbers do the same. Even for a contact pitcher, 18.8 SwStr% is pretty good. 

The only batting average against that's lower than his change is his four seam, which he barely throws (only 15 on the year so far). Also, not to be a wet blanket, but on the opposite side of the spectrum, the numbers show that maybe Roark should stay far away from his curveball. 

This one is as obvious as they get. It's the change. Moving on. 

Joe Ross

Best pitch: Slider

This may come as a surprise to some fans, but to those who watch Ross a lot, it's anything but. Sure, he's a sinker ball pitcher and a pretty good one at that. But his most effective pitch - the one he uses to get outs - is his slider. Granted, sinker balls are meant to be hit into the dirt while sliders are intended to miss bats, but still. The sliders' Swing and Contact percentages alone suggest an incredibly effective pitch, let alone when you compare it to his sinker or his change.

 

A .200 batting average against is impressive, while the .273 against the sinker is just okay, especially as his primary pitch. The .429 against the change is a victim of sample size, so exhale Nats fans.

Like previously stated, it doesn't make a lot of sense to compare a sinker and a slider when it comes to swings and misses. The slider alone, though, at 20.35% is a very good pitch. 

So there you have it, Nats fans. Your rotation thrives on the changeup mainly, with a little bit of slider on the side. 

RELATED: State of the Nats: Wins piling up, but tough stretch awaits