Giolito pitched just fine with the sticky ban last year. Yes, his spin rates are down and they've been steadily going down since the sticky ban, but he had a 3.33 ERA and 3.47 FIP in 92 innings after June 21st (when the ban went into effect) last year. The lack of sticky stuff might make it so that his fastball is no longer as effective, but he did just fine without it for about 120 innings. Here is how his 2021 went pre and post sticky ban.
Pre 6/21/2021
Fastball - 2430 RPM, .225 BA, .441 SLG, 43.9%
Slider - 2174 RPM, .250 BA, .583 SLG, 17.1%
Change - 1475 RPM, .188 BA, .362 SLG, 37.5%
Post 6/21/2021
Fastball - 2272 RPM, .270 BA, .416 SLG, 43.8%
Slider - 1943 RPM, .187 BA, .245 SLG, 25.2%
Change - 1511 RPM, .259 BA, .411 SLG, 26.9%
Giolito really had to adjust his pitching style after the ban. His fastball and slider spin rate went down by a lot. His fastball/change combo was no longer his bread and butter without the high spin rate on his fastball, as teams could sit on the change up more. He went with his slider a lot more and it was arguably his best pitch post ban. But he adjusted fine and was still considered a very good, if not elite, starting pitcher.
2022 has been rocky for Giolito with an injury on opening day and then COVID in early May. I've seen a lot of people talk about how he hasn't been the same since COVID, so I decided to take a look at the splits. He returned from COVID on 5/18 and here are his numbers pre/post.
Pre 5/18/2022
Fastball - 2170 RPM, .200 BA, .472 SLG, 48.6%, 93.1 MPH
Slider - 1980 RPM, .400 BA, .650 SLG, 19.9%
Change - 1426 RPM, .120 BA, .160 SLG, 23.6%
Post 5/18/2022
Fastball - 2155 RPM, .365 BA, .519 SLG, 48.2%, 93.3 MPH
Slider - 1954 RPM, .234 BA, .553 SLG, 28.3%
Change - 1402 RPM, .385 BA, .642 SLG, 21.7%
One thing that jumps out at you is just how bad his change up has been in his past 6 starts. It was easily his best pitch results-wise in his first 5 starts. Just from watching Giolito pitch recently, it's stuck out to me that his slider has been getting hit really hard. He's given up 4 homers off hanging sliders in his past 4 starts alone and I can actually remember all of them without looking it up. And yet, that's his been his best pitch since 5/18 because his fastball and change up have been god awful. He's also upped the usage on the slider by about 8% (mostly by ditching the curveball), so more sliders = more probability he hangs one once in a while.
So what the hell happened to Giolito's fastball and change up combo? It was once one of the best pitch combos in baseball and it's now extremely below average. I don't think it's the velocity that's the issue here. He's throwing harder since his bout with COVID. His spin rates, while down a little, aren't down enough to make you think that's the main issue. I think the main issue is his control on both pitches. Here's the heatmaps for his fastball with pre COVID on the left and post COVID on the right.
Fastball
His fastball control has been erratic ever since coming off the COVID list. He was around the zone more often than not in his first 5 starts of the year, but he has since been just about everywhere with his fastball. His 40% CSW rate (called strike and whiffs) has decreased to just 32%. He's also gone from throwing 26% balls to nearly 39%. The lack of fastball control really hurt him last night in the 6th when he fell behind every hitter and had to throw his fastball in the zone in fastball counts. Speaking of fastballs in the zone, Giolito has gotten killed on them since 5/18. Here are those numbers.
Pre 5/18/2022
Fastball heart - .278 BA, 16%
Fastball shadow - .160 BA, 22%
Post 5/18/2022
Fastball heart - .500 BA, 13.2%
Fastball shadow - .304 BA, 20%
Just for reference, the heart is basically in the middle of the plate, a few inches inside the corners of the zone. The shadow is the area around the edge of the zone. The league average on heart fastballs is .299. The league average on shadow fastballs is .223.
So either his fastball is now one of the worst in the league or he's getting extremely unlucky. A little unlucky, maybe. His xBA on his fastballs since 5/18 is about 60 points lower than his actual BA on them, but I'm not sure that's the entirety of the problem. I alluded to him getting behind in the zone and having to throw his fastball in the zone in fastball counts earlier, and weirdly enough, he's thrown less fastballs in the zone since 5/18 than prior. All this points to his fastball just being less effective overall. He's throwing it faster, he's throwing it less in the heart of the zone, but when he's throwing it there, it's getting clobbered. It's a bit astounding that even his fastball in the shadow of the zone is being hit at a .300 clip, when that should be a pitch that gets hit for about .200.
Without his ability to establish the fastball, his change up has suffered as well results-wise. But he's also not locating it as well. Here are his change up heat maps, the left is prior to COVID and the right is after.
Change
He's throwing the change up a lot less in the zone. He used to throw it inside to right handers and outside to lefties, but he's more or less just throwing them low and out of the zone. If he's behind a hitter, that's probably a pitch they end up laying off as opposed to swinging at. And that's more or less what batters have done as the whiff rate on his change up has decreased from 30% to just 10%. They're also taking the pitch about 4% more for balls. His CSW% is also down from 40% to 25%.
TLDR: his fastball and change up are crap now. His fastball is all over the place and when he throws it in the zone, it gets crushed. He's also getting behind in the count more due to lack of good fastball control. Hitters are laying off his change up and they're also hitting it hard when he does throw a hittable one. His slider has been hit hard for homers, but has more or less been his best pitch. Although that's not saying much since his fastball and change up have been horrendously bad since coming back from COVID.
How do you fix him? Get his fastball command back. The more counts he's ahead in, the more he can use the slider and change up more effectively and the less he has to throw the fastball in fastball counts. I think the days of Lucas having an elite fastball are over. He just needs it to be league average or serviceable. That hasn't been the case in the past 6 starts and that's why he's been getting clobbered.