Lucas Giolito, new and improved

When the Chicago acquired Lucas Giolito they and White Sox fans knew that he was not the same pitcher he was earlier in his career. He was not the 100 mph fastball pitcher he once was, but he was still highly rated in the usual prospect rankings after disastrous cup of coffee with the Washington Nationals in 2016.

Giolito’s 2017 with the White Sox was much better. After he lost the battle to Reynaldo Lopez for the first White Sox pitching promotion, Giolito looked like a future piece in a championship starting rotation.

And then 2018 happened (er, is happening, but keep reading).

From Giolito’s first start on March 31 until a start on August 8 (my birthday), Giolito was awful, and fans seemingly gave up on him. His velocity was way down for most of that stretch, and his average game score was 43. In other words, he kind of deserved to be overlooked. But from August 14 on, Giolito has been a different pitcher. He revert neither back to his Nationals days nor his 2017 White Sox performance. Was it my private birthday wish that Giolito break out of his slump and pitch like an ace again? I won’t tell. But what I can tell you is that Giolito is now a new pitcher, and a much improved one.

Velocity

Velocity was a huge problem for Giolito early in the season, especially for his fastball and slider. From the start of the season through August 8, his average velocity was in sync with 2017 Giolito (fastball 92.6 mph, slider 83.9 mph) and both were trending upward as the season wore on.

From August 14 on, Giolito’s fastball has averaged 94.3 mph. That includes his August 25 start, where he reached 95 mph with regularity for the first time in his MLB career. Meanwhile, the slider has averaged 85.3 mph.

What Giolito is doing is throwing harder than ever before, including 2016. However, his pitch sequence is the real reason Giolito is a whole new pitcher.

Pitch Sequence

Look at any prospect overview on Giolito: There will be rave reviews on his curveball and to an extent his fastball, and for good reason. Even when he struggled, Giolito would show us a great curveball or two in a start, and good movement on his fastball. But those breakout pitches were few and far between. Recently, Giolito has started to use two pitches that have not even been on his radar before: his sinker and changeup.

In the short stint with the Nats in 2016, Giolito’s sinker was used 1.3% of the time, the changeup 10.6%. In 2017, the sinker and changeup both bumped up in usage, to 9.7% and 16.1% respectively, but Giolito was still, predominantly, a fastball pitcher. For much of 2018, it was the same: Up until August 8, the sinker was used 12.4% and the change at 14%, but in the latter half of the stretch, both were being used more. However, neither pitch was very good, as you can see from the splatter of red below.

FanGraphs

The reason why August 14 is the cutoff is that in every start from there, Giolito has used the sinker more than his fastball, which he had only done in a handful of starts previously. From August 14 up until his last start, he has used the sinker 40.7% of the time, and the changeup at 21%. The surprising thing about his new pitch sequence is that he is only using his fastball 16.8% of the time, and his results are a complete U-turn, with much more cool blue.

FanGraphs

So, is Giolito good again?

Heat maps are great and all, but good hard stats are much more effective in answering the question above. Let’s start small and get broader as we go (spoiler: yeah, Giolito is good).

From a pitching perspective, it is not hard to discover why Giolito was struggling earlier in the season. In his five-pitch repertoire, only two pitches had a positive value per 100 pitches, the changeup (0.13), and slider (1.35). His fastball, which was primarily used, was at -0.94, the sinker was at -1.74, and his supposed best pitch, his curveball, was at -2.72. Although those pitches are still down with the new pitch sequence, good luck hitting them when they are good.

When Giolito changed his pitch sequence to feature his sinker and changeup, his pitch values changed accordingly. The fastball (-4.42), slider (-2.89), and curveball (-3.19) have gotten worse, but he has avoided using them. The sinker has risen to 1.53 and the changeup, his supposed worst pitch as a prospect, has risen to an all-time high of 4.45 per 100 pitches. So in effect, 60% of his pitches since August 14th have brought Giolito positive success, unlike his previous pitch sequence. And yes, the velocity gain in the fastball has helped his changeup.

Before the true uptick in velocity and the pitch sequence change, Giolito was not getting many swings, and allowing too much contact. From March through August 8, his outside the zone swing percentage (o-swing) was at 24%, and that’s not great. He was also allowing contact at a 81% rate on all pitches, which led to an abysmal batted-ball profile. Giolito was allowing 41% of his batted balls as fly balls, while his pull percentage at 41.9% indicated the good contact he was allowing.

From August 14 on, it has been a much different story, as 32.1% of Giolito’s pitches outside of the zone has garnered a swing — a much better number. On top of that, the contact percentage has improved to just 78.2%. Both numbers are not elite, but are much better and more representative of a future starter on a championship contender ,which led to a much better batted-ball profile. The majority of batted balls are now ground balls (52.6%), as Giolito only allowed 30.5% fly balls. To emphasize how much better Giolito has been with his new sinker-changeup approach, his pull percentage is at a low 35.8%.

If the minute and and peripheral starts did not convince you, this will. Giolito’s average game score from March through August 8 was 43, with a 6.23 ERA, 6.00 FIP and a 5.95 xFIP. Yes, that is absolutely terrible — but even worse was his 6.02 K/9 and 5.08 BB/9.

From August 14 on, Giolito has a 4.01 ERA, 3.72 FIP, and a 3.60 xFIP. That is helped by an 8.82 K/9, 2.67 BB/9. That is not ace stuff, but it is night and day compared to earlier this season.

It is hard to be patient with top prospects, especially with Ronald Acuna and Juan Soto kicking ass, but like I said in July about Tim Anderson, Giolito has proven in the last month that he deserves our patience.