What’s Going On With Shane Bieber?

Shane Bieber has been one of the best pitchers in baseball in recent years. From 2019-21, he used pristine command and nasty breaking balls to rack up elite levels of strikeouts while posting an ERA- of 64 (tied for second-best in baseball over that span); he even won the AL Cy Young Award in 2020. That elite level of performance lasted until a 2021 shoulder strain cost him over three months of the season; he returned just in time to make a couple of late September starts before officially shutting it down. Coming into the 2022 campaign, Bieber said he was “100%.” Yet through his first eight starts of the season, there are warning signs all over his underlying metrics:

Bieber has still been an effective pitcher. He has an above-average ERA and an even better FIP and SwStr%, but these numbers still represent a drop in performance. For a pitcher who is just shy of 27 years old, it’s certainly notable, but we might chalk it up to a wonky eight-start rough patch were it not for the dip in velocity and the injury last season. But Bieber has lost three ticks on his heater from his Cy Young peak, when he averaged 94.3 mph. I wonder if we might be seeing the lingering effects of his shoulder injury. Just prior to the injury, Bieber’s velocity dipped to 92 mph and during his late September cameo, it was down to 91.4 mph. Throughout the season’s early going, Bieber has been asked repeatedly about his velocity dip and insisted that he feels fine and expects his velo to trend up as the season goes on. As we reach the end of May, however, no such increase has occurred:

Regardless of the cause, it isn’t a good development. And beyond just the lost velocity, there are some interesting mechanical changes that are worth taking a closer look at. We’ll start with an establishing shot of Bieber’s mechanics in 2020 and then this season. You may be able to pick up on some changes, like how this year’s windup is quite a bit faster:

Next we’ll look at his arm path. The following clip is synced to when his front foot lands, giving us a better look at his hand position at that pivotal point in a delivery. To me, it looks like his entire upper body is more closed off, giving Bieber a more circuitous hand path from his glove separation all the way through to the release of the ball. The result is an arm that needs to play catch-up as his foot lands:

These mechanical changes could mean a number of things. It’s possible this is an intentional change to try and add velocity, or to mitigate a recurrence of his shoulder issue. Or these could be subconscious changes as Bieber’s body tries to find a pain-free path to delivering a pitch. If you want to assume that this change is part of the loss in velocity and that it’s helping him stay healthy, then it could be a worthwhile tradeoff. However, if this is a less intentional tweak and it’s the result of his body subconsciously favoring his shoulder, it could lead to added stress on other areas that are currently healthy.

Given that we’re about a quarter of the way into the season, we have a pretty good sample by which to gauge how Bieber is trying to pitch through his velocity decline. It might seem like the obvious solution to a diminished fastball would be for Bieber to lean in to his two good breaking balls. Look no further than the success of Clayton Kershaw in recent years for a blueprint to mimic. Kershaw has evolved from throwing 94 mph fastballs 60% of the time to throwing a 91 mph fastball only 36% of the time. He is now a slider-first pitcher and it has allowed him to have a tremendously successful decline phase – if you can even call his 72 ERA- over the last five seasons a decline. A Kershaw-like evolution from Bieber may not be so straightforward, however, as he’s never relied on his fastball nearly as much as Kershaw did and has always heavily featured his breaking stuff. In fact, it may come as a surprise to see that Bieber hasn’t decreased his fastball usage at all; at 38.3%, it’s pretty much right in line with his 2020 season:

Bieber’s continued use of his declining fastball has come at a cost. While his wOBA allowed on his fastball is only .364 so far this season, his xwOBA has risen somewhat ominously up to .435, compared to .320 last season and .290 in 2020. Instead of throwing fewer fastballs, Bieber has opted to change his breaking ball usage, throwing more sliders in lieu of his curveball. The problem is that his slider hasn’t been that effective for him this season (.300 wOBA, 18.8% SwStr%) after being one of the best sliders in baseball last year (.207 wOBA, 24.8 SwStr%). More than just its increased usage, the movement profile of the pitch has undergone a change as well:

Bieber is getting significantly less depth on his slider while gaining a small amount of horizontal movement. These changes come from him putting more back-spin on the pitch than in years past; previously, the spin he imparted on the ball was much closer to that of his curveball. As a result, his slider has more cutter-like qualities and he’s lost about 200 rpm from last year, leading to a pitch that is generating fewer whiffs and fewer swings outside the zone than at any other time in his career. If you look closely, you can see the subtle change in his fingers, which are pushing a bit more behind the ball, giving the pitch a touch more backspin than before:

These changes to his slider have given him a bigger movement and velocity difference between his slider and curveball, which is helping to diversify his arsenal after years of having a slider and curveball that were eerily similar. But it’s hard to say whether this is a good change, especially considering that it is now his most used pitch. His curveball, on the other hand, has been his best pitch (.201 wOBA, 16.8% SwStr%) and may be benefitting from these changes to his slider.

This new movement profile coupled with the mechanical changes highlighted earlier may be creating some issues when it comes to his typically great command of the pitch. Bieber is currently leaving double the number of sliders up in the zone compared to 2020. Check out his slider heat map and you’ll get a better sense of the frequency of his mistakes this season:

There’s been a lot of doom and gloom in this piece so far, and I would like to leave things on a more optimistic note. For that, I’ll mention Bieber’s most recent start against Detroit last Sunday afternoon. Things were a bit rocky in the beginning, with Miguel Cabrera ripping a hanging slider for an RBI double, but Bieber eventually settled in to what turned out to be a dominant performance. It was the best his slider has looked since before his injury. He found success with the pitch by consistently commanding it to the low-and-away corner, earning whiffs all afternoon — he generated 11 whiffs on 39 such pitches thrown (28.2% SwStr%) with an 84.9 mph average exit velocity. On the day, he notched a season-high 10 strikeouts over seven innings.

Of course, it’s only one start and it came against the Tigers and their league-trailing offense. Bieber’s fastball velocity didn’t tick up any, and even though his slider was great, none of the underlying metrics suggest it was all that different from what it has been in previous starts this season, still lacking the spin rate and vertical bite of years past. But that doesn’t have to mean that this start is an aberration. Bieber could be finding better ways to use his slider, and his command of the pitch could be improving as he gets more used to its new movement profile. Bieber really needs his breaking pitches to carry the weight if he’s going to remain successful with below average fastball velocity, and this outing serves as a proof of concept for how he can still dominate a lineup even if his Cy Young stuff stays firmly in the rear view mirror.