(Note: if you want, you can read this whole article as if I am trying to talk myself off a ledge. I'm fine with that.)
24-year-old Kevin Gausman likely is a permanent fixture in the rotation after the Bud Norris was DFA’d in July. Giving Gausman the chance to start every day is something Orioles fans and pundits alike have been clamoring for ever since the flamethrower was called up in 2013. Since then, Gausman has been yo-yo’d between AAA and the majors, and between starting and relieving, a number of times. It seems like only now has the club has committed to giving him a chance in the starting rotation.
During these same years, baseball fans have been treated to a number of young hurlers who throw in the mid-90s. Stephen Strasburg, Matt Harvey, Jose Fernandez, Gerrit Cole, Yordano Ventura, Noah Syndergaard, Carlos Martinez, Zach Wheeler, Chris Archer, Danny Duffy … the list goes on. In aggregate, these pitchers have been quite successful, and their combination of youth and fastball speed has led to many hagiographies.
If you’re looking only at on-field success and comparing against this list, Gausman may seem like a disappointment and is even taking a step back this year. Right now he’s sporting a disappointing 4.56 ERA and seems to be giving up home runs by the bucketful. His last pitch resulted in a two-run double that gave the Angels a 5-4 lead over the Orioles.
I was frustrated enough with Gausman’s recent outing to look at why he might not be an ace. I want the Orioles to have their own Gerrit Cole, dagnabbit! In so doing, I found some useful tidbits. Gausman is using his fastball higher in the zone and he has shelved his slider, which was getting hit all over the place, for a curveball. But beyond those details I discovered something more useful: that Kevin Gausman is actually a decent pitcher already and that I shouldn’t let one grooved fastball determine how I feel about a pitcher’s talent level.
Because looking beyond the surface shows that Gausman is very close to the same pitcher he was last year, and in some ways he's even better. How so? His swinging strike rate is up 1.5 percentage points, his strikeout rate is up 1.1 percentage points, and his walk rate is down 1.8 percentage points. When combined, his K-BB% is 2.8 percentage points better than last year’s, going from below league-average to above league-average. These are signs that he’s developing as a pitcher. His groundball rate has also increased a tick.
"Yes," you may say, "but he’s giving up lots of home runs!" To you I would reply: "He is, but not because he’s gotten worse as a pitcher." Rather, his HR/FB rate is regressing to the mean. Last year it was a miniscule 5.8% on the back of a 35.3% fly ball rate. As I wrote in last year’s recap of Gausman’s season, this rate likely was unsustainable. In that light, his current HR/FB rate of 10.3% with a flyball rate of 41.2% is quite good. Far from a decrease in skill, one might even say he is benefitting from good luck in this department.
Finally there’s the matter of that ERA (and if you like, that FIP). Part of the explanation lies in the HR/FB rate. But a bigger part can be explained by Gausman pitching much worse with men on base than he is with the bases empty. When no one’s on, batters are hitting .246/.285/.369 against him. That’s a .287 wOBA, which is quite good. With men on base, his batting average against goes down to .241. However, his OBP and SLG against rise to .318 and .500 (!) respectively. That’s quite a different, quite worse wOBA of .343. It's the difference between facing light-hitting Erick Aybar and MVP candidate Buster Posey.
This split, which is a sample of just 88 batters or about three games, is why so many runs are scoring against Gausman despite a good-looking K-BB% and HR/FB rate. The metric to look at here is left-on-base percentage, or LOB%. Gausman’s this year is around 66% vs. the league average of 72%. LOB% is another metric whose extreme deviations tend to regress to the pitcher’s career levels. Its current value, unlike strikeouts or walks, is not very predictive of the future.
Overall, his xFIP of 4.16, which strips out batted ball and HR/FB luck, is very close to last year’s 3.93. Over the course of 180 innings, that is a difference of just 3.2 runs, less than half a win. And Gausman won’t even pitch that much. If you prefer plain FIP, Gausman looks even better when you adjust for park and league: his FIP- is 99, 1% below league average. And on top of all this, he's 24 years old and can touch 101 on the radar gun.
Gausman’s good 2014 (specifically, his low ERA) was somewhat of a mirage. Last year his absurdly low HR/FB rate masked a below-average strikeout rate and an above-average walk rate. Without this context his 2015 can seem alarming. So get frustrated by the runs he's allowing, but understand that underneath it he's mostly the same pitcher, perhaps even a little better.