Meet the Ace: Lucas Giolito

Lucas Giolito has become the White Sox Ace in 2019. Let’s take a look at the road to get to where he is today.


June 4, 2012. 16th Overall Pick. $2.925M Signing Bonus.

Fastball: 80 | Curveball: 65 | Changeup: 55 | Control: 55 | Overall: 65

These numbers, along with Lucas Giolito’s Top 10 Prospect Ranking (#1 RHP Prospect), have defined his career to this point. Everyone expected him to be the next “guy.” He made a short debut in 2016 for the Nationals and struggled. Then, he was traded to Chicago, had a decent 2017 debut, then was the worst pitcher in 2018. Through his struggles, we’ve seen a pitcher who couldn’t command his best pitch: his fastball. This lack of command affected every other pitch he threw. “Repeatability” is the key word you’ll hear when talking about Giolito: he couldn’t command the zone because he couldn’t command his 6’7″ frame with consistent mechanics.

Because of this, fans have been calling for the “bust” label to be placed upon Giolito for awhile. Fans ignored his pure ability – understandably – due to the results on the field. Here are some of my favorites:

But then, 2019 came. Giolito came to camp with an improved mental toughness and improved mechanics. After spending the Spring focused on process rather than results – as any good pitcher does – Giolito has turned himself into an Ace at the time the White Sox have needed one most. Every team, no matter rebuilding or not, needs a “stopper” – someone whose turn comes around in the rotation and brings confidence of a win. That’s Giolito right now. With a 6-1 record, 2.77 ERA, and 2.78 FIP, the Giolito we are seeing looks to be here to stay. Let’s look at how he’s done it, and explain why he’s not only in line for an All-Star appearance, but a front-runner for Comeback Player of the Year.

Tale of the Tape: Giolito’s 2019 Statistics

What the Numbers Say

Lucas Giolito has been a top 15 pitcher by most metrics in MLB to start this season. Here are just some of his numbers, as well as his MLB ranks:

fWAR: 1.8 (T-4th)

ERA: 2.77 (14th)

FIP: 2.78 (8th)

ERA+: 161 (12th)

K/9: 10.2 (14th)

WHIP: 1.06 (15th)

These numbers say a few things about the season Giolito is having (mostly positive), but none is more important than his ERA/FIP values. For his ERA and FIP to be exactly the same means the results – while most likely subject to some regression – are not a fluke. Consider his 2017 season, almost a foreshadowing of his horrendous 2018. His ERA in 2017 was 2.38. However, his FIP was 4.94. When a player’s ERA and FIP are incredibly far off, in the long run, the pitcher tends to wind up closer to his FIP value by the end of the year. So, with minimal changes from 2017 to 2018, it really wasn’t much of a surprise to see him struggle so mightily. Yet, what we are now seeing is a pitcher who is commanding the zone and commanding his pitches. As a result, he has become one of the most valuable SP to start this season.

The more important question is: How has he done it? Let’s explore.

How Giolito Has Gone From “Bust” to “Boom”

New and Improved Mechanics

We know Giolito made a huge change in mechanics coming into the season. He is using a much shorter, much more repeatable arm motion. Here are just a couple videos of fastballs from 2018 and 2019:



A couple quick notes, since the changes are fairly obvious and a lot of people have already written about them:

  • Repeatability is the most important thing for a pitcher – and even more important when you’re 6’7″. When you’re a tall, lanky dude, it is much harder to control your body (or so I’ve been told, considering I’m 5’7″ on a good day). Giolito’s huge frame resulted in a long arm motion that, if I had to guess, would result in him not really knowing where the ball was going to end up most of the time. Shortening this is 2019 has made his mechanics repeatable and, far more importantly, simpler. Baseball is hard enough as it is – players don’t need to make it harder on themselves.
  • Giolito also hides the ball a lot better this year, and I think that has paid dividends on getting away with some pitches he probably shouldn’t have.
  • Basically, if you remember three things: Shorter, Quicker, Smoother. That’s what Giolito changed from 2018 to 2019.

Ditch the Sinker

Now let’s move past the mechanics and see how they’ve affected the rest of Giolito’s game. The first big change Gio’s made (though not at all related to the new mechanics) was ditching his sinker. After increasing the use of his sinker to about 20% in 2018, Giolito has not thrown it at all this year:


This was probably for the best: hitters slugged .445 off of it last season, with a wOBA of .338. After ditching his sinker, Giolito has turned back to his two best pitches: his fastball and his ever-improving changeup.

Command, Command, Command

This section speaks for itself. Simply put, Giolito is locating the zone a lot more often in 2019 than he did before. To start, in general, he has thrown 10% more strikes in games than he did in 2018. He has thrown a first-pitch strike to 63% of batters – a 15% increase compared to 2018.

Command is so important because if hitters see a pitcher throwing more strikes, they are going to swing at more pitches that look like strikes. This last graph shows some of my favorite numbers from 2018 to 2019 (just ignore the 2016 and 2017 numbers):


So, from 2018 to 2019, Giolito is getting hitters, in general, to swing 4 percentage points more often (47% Swing% in 2019) this season, but they are making much less contact on pitches both in (Z-Contact%) and out (O-Contact%) of the zone. It is for this reason that we see Giolito’s K% currently sitting at 28.5% – he is a more deceptive pitcher to begin 2019 than he ever was in 2018. This starts, primarily, from a better command of all his pitches, which stems from his change in mechanics.

New Life on the Fastball

In 2018, Giolito’s average fastball velocity sat at 92.4 mph. This season, he has added over 1 mph to his fastball speed, now sitting at an average of 93.7 mph and – as we saw last night – routinely hitting 96-97 mph on the gun. With this increase in velocity has come an increase in the spin rate on his fastball, from 2099 rpm (rotations per minute) to 2270 rpm. This increase in spin rate has given his fastball new life in terms of its “rise” – his fastball now rises 11% more than the average fastball at his given average velocity. Basically, this means that, in a game fascinated with launch angle, Giolito is missing more bats by getting guys to swing under his rising fastball. Now, after slugging .524 last season off his fastball, hitters are hitting .256 with a .367 SLG. Much improved.

The second improvement has been with his two-strike approach when throwing fastballs. With two strikes, Giolito has always worked up in the zone with his fastball. However, due to his subpar command, velocity, vertical break, and spin rate, his high fastballs were either A) not high enough, or B) not deceptive enough in 2018. However, with improved command and velocity, Giolito has been able to command the high fastball consistently this season, resulting in a 20% K% and 18.8 Whiff% on his fastball in 2019 (up from a 13% K% and 14.3% Whiff% in 2018):

Fastballs (2018 on Left)

There were some pitches in 2018 that were so far out of the zone that I couldn’t even tell if they were part of the graphic for a slider or fastball on BaseballSavant. The 2019 version of Giolito has new life and new command of his fastball that has paid dividends early on this season. His ability to command the high fastball has been crucial to his success.

New Two-Strike Approach With Offspeed

Giolito has taken an interesting approach to 2-strike counts this season. In general, with two strikes, he has thrown changeups away to lefties and sliders down and away to righties. The best part is how well he has commanded these pitches. Here are some comparisons on two-strike counts from 2018 and 2019 with both his changeup and slider. The 2018 heat map is always on the left side of the page:



The difference is especially apparent in the changeup graphics. Giolito is harnessing the horizonal movement of his changeup much more this season (AKA: he is working left to right just as much as he is working up and down with his changeup). Both graphics also depict the same general takaway as the fastball graphic: improved command of pitches. However, equally as important to this new and improved two-strike approach is the difference in velocities of his pitches.

Dramatic Difference in Pitch Velocities

In order to be effective as a pitcher, you need to not only command the zone, but mix speeds effectively. Pitches need to look similar (pitch tunneling – think PitchingNinja videos) but be different enough in velocity that they are deceptive. You’ve heard the rules: 10 mph difference between fastball and changeup being one of them. In 2018, Lucas Giolito just did not have a consistent difference between his pitch velocities.



In a nutshell, his fastball, on average, is faster, and each of his offspeed pitches is slower. He has created a wider velocity difference between his offspeed pitches and his fastball. Even on a pitcher’s worst day, his fastball and slider graphs shouldn’t overlap like they do in 2018, even if it is at the extremes.

This is why his two-strike approach, while incredibly easy to pick up from the data, is so effective. His pitches look the same out of his hand, but come in at dramatically different velocities and with improved break. So, if a hitter guesses wrong on what pitch is coming, he is less likely to hit it due to the dramatic differences in speeds. If a fastball and a changeup are too similar in speed, hitters are able to adjust and hit them hard, even if it wasn’t the anticipated pitch. The 2019 version of Giolito has eliminated this.

Through each of these different changes stemming from his mechanics, Lucas Giolito has completely transformed himself as a pitcher in 2019. His numbers are the direct result of an offseason worth of work on his mental toughness and mechanical changes, and he (and his old high school pitching coach) should be credited for the amount of work put in to get him back on track to be the front-of-the-rotation starter he was projected to be.

What Could Giolito’s 2019 Have in Store?

All-Star? Think Bigger

Let’s start with the facts: top 15 pitchers make All-Star rosters. Better yet, top 15 pitchers who play on less-talented rebuilding teams have an even better shot of making the All-Star roster. Should the Lucas Giolito we have seen so far this season continue his tear through the American League, there is no reason he shouldn’t be one of the guys the AL runs out there in Cleveland in July, especially from a team without many proven stars like the White Sox. Regardless of team, his numbers serve as proof that Giolito is not only an improved pitcher, but one who can make a front-of-the-rotation type impact.

But, let’s think bigger. According to my good friend Wikipedia, The Major League Baseball Comeback Player of the Year Award is presented to the player who is judged to have “re-emerged on the baseball field during a given season.” While in most cases, this award is reserved for a player who comes back from injury, there are several examples of players who win this award for an extreme improvement in performance. I can’t think of a much better re-emergence onto a baseball field than a former #1 prospect who was drafted, needed Tommy John Surgery, struggled in his first few stints in the big leagues, was the consensus worst pitcher in 2018, yet became one of the game’s best in 2019. It’s a long way away, but 2019 could be a storybook-type season for Lucas Giolito. On a team that has been waiting for its starts to arrive, here’s hopes that this one is here to stay.

A Final Word

I’ve stayed away from any “I told you so!” moments throughout this article, and I hope it was incredibly informative to understanding why the Lucas Giolito you’re seeing should be here to stay. BUT, since we love the ChiSoxWeekly guys over here, I want to make a quick shout-out to constant Giolito doubters ChiSoxJonda and Mr. Tony Marchese. Go back on many a conversation between the three of us on Twitter in the past year and see what I’ve put up with for defending Giolito. I’ll let this one tweet, however, speak for itself…..

Let me know your thoughts on Twitter! @jlazowski14

Featured Photo: Our Amazing Graphic Designer Brandon Anderson (@b_son4)




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