While there have been plenty of dominant pitching performances so far this season, some of the biggest names at the position have been left out of the fun. Lucas Giolito, Luis Castillo, Kenta Maeda and Kyle Hendricks have been flat out bad in the early going, while even an elite arm like Shane Bieber has hit a bump in the road of late. When you're watching everyone else's pitchers dominate, it's easy to panic about your struggling studs and to cast about for explanations.

One explanation I've seen thrown out there by some of our readers and listeners is that, due to changes in the composition of the baseball being used this season, perhaps some pitchers are simply struggling to get a feel for their best pitches. This is a reasonable assumption -- we saw something similar back in 2019 with guys like Masahiro Tanaka and Edwin Diaz struggling with their best pitches -- but I've seen some suggest that it could specifically be related to changeups. After all, Giolito, Castillo, Maeda and Hendricks all count a changeup among their signature offerings. Maybe the new ball is just making changeups less effective overall, for some reason. 

On the whole, there doesn't seem to be that kind of easy explanation, however. For the league as a whole, changeup usage is slightly down from 11.8% to 11.6%, which is still higher than any other season in the past decade (at least). Expected wOBA allowed on the pitch is .290, which is actually lower than both 2019 and 2020, while the actual wOBA on the pitch is down to .275 -- the previous low in the last decade was .287, back in 2014. 

The overall swinging strike rate on changeups is down a tad, from 16.1% in 2020 to 15.4% in 2021, and the whiff/swing rate is down from 31.9% to 30.6%. So, on the whole, maybe changeups have been a bit less effective as swing-and-miss pitches than they were last season, but that's not necessarily evidence that there is a "changeup problem," so to speak. 

Those high-profile pitchers who have struggled with their changeups stand out, and it's certainly possible some changes to the ball have made them individually struggle to throw the pitch effectively. But it's not like changeups are the only pitch high-profile pitchers are struggling with. 

For instance, while Giolito hasn't been the guy we've come to expect, it's not his signature changeup that has been the issue so far: It's been his slider. And, while Castillo's change hasn't been as dominant as we're used to seeing, it has still been a very good pitch; it's his fastball, and especially his sinker, that have been getting absolutely rocked. 

And they aren't alone. I compared's pitch value data from 2020 to 2021 to identify the high-profile pitchers who have, at least so far, been let down by some of their go-to pitches. Here are some of the key names, the pitches that haven't been as effective as normal for them, and whether there is truly reason to be concerned:

  • We break down other struggling players including Lucas Giolito and what to do with them on the latest Fantasy Baseball Today podcast. You can subscribe to make sure you get the latest episodes when they drop on Apple and Spotify.

Lucas Giolito - Slider

Giolito's slider is firmly his No. 3 pitch, but it's an important part of his arsenal to put away right-handed hitters -- he has thrown the slider 28% of the time against righties in two-strike counts, compared to 25% for his signature changeup. Giolito has been better against left-handed hitters ever since his breakout, but he allowed a .224/.293/.387 line to righties with a 32.9% strikeout rate against them in 2019 and 2020 combined; righties are hitting .259/.310/.556 with a 27.6% strikeout rate against him this season. That explains much of his struggles because his whiff rate on the slider has fallen from 52.6% in 2020 to just 30.8% in 2021. He's throwing the pitch harder this season and getting less drop while his fastball and changeup mostly look the same, which could help explain why it hasn't been as effective. This seems like a relatively small fix for Giolito, who has shown the ability to tinker in-season before, and I'm not at all worried about his chances of figuring this out.  

Luis Castillo - Fastball, changeup

Given how much the pitches play off each other, it's little surprise that both Castillo's fastballs and his changeup have been less effective, and since he throws them around 85% of the time, that's a problem. Though, as I said before, Castillo's changeup has actually still been a very good pitch for him --  a .300 wOBA and .254 xwOBA aren't quite what we've come to expect -- and the 26.2% whiff rate is well south of expectations, which helps explain much of his strikeout problem -- but it's still been a very effective pitch for him. The problem is primarily the sinker, which has been crushed for four homers and a .923 slugging percentage. His average velocity is down 1.4 mph from 2020, which has been cause for alarm, but it's only 0.4 down from 2019, when it wasn't nearly as much of an issue. 

This has been an incredibly concerning start for Castillo, to be sure, and the fact that he used the changeup just 12.8% of the time in his most recent start is especially concerning -- if he doesn't trust that pitch, Castillo isn't going to be an effective starter. However, his pitches generally don't look that much different -- the velocity isn't dramatically lower, and the movement and spin profiles all look pretty much the same -- which makes me think this is more of an execution problem than a pitch problem. Maybe he's tipping his pitches. Maybe his mechanics are just off. Either way, with no obvious explanation, I'm going to continue to assume Castillo will be fine in the long run. I'm still putting buy-low offers out there. 

Kenta Maeda - Fastball, slider, splitter

Other than that, how was the play, Mrs. Lincoln? In Maeda's case, as with Castillo, the slider and splitter haven't actually been bad, they've just been less effective than in year's past. However, there's a bit of bad luck involved here as well: Maeda has allowed a .387 wOBA to opposing hitters compared to a .353 xwOBA. That xwOBA would still be the worst of his career by a wide margin, however, so it's not exactly good news. Maeda is older than you think at 33, and it's not unreasonable to think he might have just declined at this point. But this is such a steep decline without much explanation -- velocity, spin rate and movement profiles for his pitches all mostly look like they are supposed to -- that I'm willing to continue to assume he'll turn things around. 

Kyle Hendricks - Fastball, curveball, changeup

Hendricks' calling card throughout his career has been his ability to limit damage on contact, which is how he continuously confounded projection systems and skeptics despite his middling strikeout rates. That hasn't been the case this season, as he has a .423 expected wOBA on contact, compared to a .339 career mark -- average is .363 for the league. Even in his very good start Sunday against the Tigers, Hendricks allowed 12 batted balls with an exit velocity over 95 mph. Many of those balls were hit on the ground, which helped limit the damage, but he still isn't quite right. 

The four-seam fastball has been his worst pitch -- opposing hitters are slugging 1.037 against the pitch -- but the changeup is the bigger concern because that's been his best pitch, historically. That hasn't been the case this season, and even Sunday he allowed an average exit velocity of 92.9 mph on eight batted balls on the pitch. As with the others here, there isn't really an obvious explanation for why Hendricks' signature pitch hasn't been working for him. He's getting a little less separation in velocity between the change and fastball -- 6.9 mph compared to 7.6 last season -- but that isn't so dramatic that you would expect this kind of difference in results. 

My hunch is that, as with Castillo and Maeda, Hendricks just isn't executing his pitches as well as he normally does, but it's also worth considering that Hendricks' profile may not leave him with much of a margin for error. Because he allows so many balls in play due to his low strikeout rate, he has to be elite when it comes to limiting damage on contact to be the kind of must-start Fantasy pitcher he's been in the past. While someone like Trevor Bauer can afford to lose a few points of strikeout rate or allow a bit more hard contact because he excels in both areas, Hendricks really only has the one trick. This season, that trick hasn't been as effective, and it's a little harder to believe he'll be fine than everyone else here. 

Shane Bieber - Fastball, cutter, curveball, changeup

Hold on, how can Bieber have a 3.17 ERA while getting worse results on most of his pitches? Well, 2020 was a pretty ridiculous outlier season for him, so regression across the board was to be expected. It's not actually as bad as that list of pitches makes it sound, but there have been some real changes here that are worth noting. In 2020, he threw his cutter 16.2% of the time and his slider 11.6% of the time, per StatCast, and they were clearly two distinct pitches; this season, StatCast has Bieber throwing his slider 26.6% of the time and his cutter just 2.3% of the time. However, the two pitches seem to be merging into one -- his slider velocity is up 1.5 mph (his overall fastball velocity is down 1.2 mph) while he has lost a significant amount of drop on the pitch. 

The slider has been Bieber's best pitch so far, so it's not like this is a problem, especially since it's not like his cutter was this dominant pitch in 2020. However, Bieber does have an 8.7% walk rate, the highest of his career, and I'm wondering if trading cutters for sliders might be playing a part in that. The slider is a better swing and miss pitch, but the additional movement likely makes it harder to command.

Bieber is throwing his curveball and slider a whopping 58.2% of the time, up from 37.9% in 2020, but he's actually not really garnering many more swings and misses, overall -- his contact rate allowed is up slightly to 63.9%. And while he's been excellent overall, there have been some bumps in the road recently that have caused some consternation among some of you in our Twitter mentions and in our email inboxes.

All in all, there isn't really anything to worry about with Bieber, who continues to profile as one of the very best pitchers in baseball. But he's made some changes to his approach that have, at least so far, made him a worse pitcher than he was in 2020. He was never going to sustain 2020's dominance, but there may be more of a gap between Bieber and Gerrit Cole (and a healthy Jacob deGrom) at the top of the SP ranks if current trends continue.