An Assortment of Reliever Signings, Part Two

So many relievers have found new homes recently that we’ve written not one, but two reliever roundups! You can find the first one from Luke Hooper here. This is part two, containing four additional relief arms who bring interesting backgrounds, stuff, and deception to the table. Without further ado, let’s get a closer look.

Brewers Sign Brad Boxberger

If you like weird, enigmatic relievers, then Brad Boxberger is the guy for you. He’s reuniting with the Brewers on a one-year, $2.5 million contract and looks to continue his success from last season. Let’s get into what makes Boxberger tick. Here’s a plot containing every reliever in 2021 who threw at least 50 innings. On the x-axis is chase rate, or how often batters swung against a reliever’s out-of-zone pitches. On the y-axis is overall strikeout rate:

That’s right. Boxberger, the point in yellow, generated an above-average strikeout rate for a reliever (31.2%) while having the fourth-lowest chase rate (20.6%). Not that more chases automatically equals more strikeouts, but this is still pleasantly odd. Boxberger doesn’t need to fish outside the zone to rack up strikeouts – he meets hitters in the middle, and more often than not, he emerges victorious.

Making things confusing is that he doesn’t have remotely the best stuff. His primary weapon is a four-seamer featuring run-of-the-mill velocity and movement. It’s not like he throws from a funky arm slot, and his vertical approach angle isn’t conducive to pitching at the letters, either. His secondaries, a slider and a changeup, are fairly bland as well. But Boxberger does have one unique trick up his sleeve, and that’s the pace of his delivery. Consider this fastball that induced a swing-and-miss:

At first, Boxberger’s delivery is unassuming. Up until his shoulders open up, he looks like a dad playing catch! But that’s all a set up for what follows. The righty rotates his trunk at an incredible speed, propelling his body into a dynamic lunge forward that contrasts the actions beforehand. My guess is that this catches hitters off guard, elevating Boxberger’s results from merely average to good. While I do think his strikeout rate will end up falling – he can’t sustain this forever – it’s a good investment by Milwaukee, whose bullpen could use a few reinforcements for a team that’s aiming to contend.

Red Sox Sign Jake Diekman

Jake Diekman, whose contract terms are still unknown, can be summarized with three attributes: He walks a ton of batters, but also strikes them out, and he limits the amount of hard contact they manage against him. Last season, however, the third part of that formula fell apart. His expected wOBA on contact (xwOBAcon) skyrocketed to .419; for reference, his career average including 2021 is .347. Which makes you wonder – what happened?

While the slider remained excellent, inducing whiffs and awkward contact, hitters absolutely tattooed his four-seam fastball. Nothing really changed in terms of location, but consider how the pitch’s movement has shifted over the past three seasons:

There’s a significant jump in vertical movement from 2019 to ‘20, a gain that Diekman mostly retained the following year. “The more ride on a fastball the better” is a modern pitching truism, but I have a sneaking suspicion that Diekman’s case is an exception. In the past, his four-seamer resembled a sinker that zagged horizontally with minimal vertical break. By adding ride, Diekman made his heater less of an outlier and thus easier to pick up out of hand. If you’re looking for evidence beyond the numbers, here’s a comparison between Diekman’s 2019 delivery (left) and his ’21 rendition (right):

He began throwing from a higher arm slot, which explains how he was able to coax vertical break out of his fastball. And while this might lead to additional whiffs, I’d argue it also made him susceptible to hard contact. The best version of Diekman seems like his 2018-19 self, and it’s now up to the Red Sox to determine how they’ll bring out the best of the veteran lefty.

Mets Sign Adam Ottavino

The 35-year-old Adam Ottavino finds himself in Queens on a one-year, $4 million deal. His slider is still one of the most ridiculous pitches around, an alien saucer that seemingly starts at one end of the plate and ends up at the other. The problem? It’s not getting whiffs like it used to. What’s worse, this isn’t new. Ottavino’s strikeout rate has been on a downward slide since 2018, and it’s gotten to the point where it isn’t enough to compensate for an outsized walk rate.

I’ll be honest with you – I don’t have a clear answer as to why. The stuff hasn’t deteriorated; Ottavino is actually throwing harder than in years past, and he’s barely lost movement on that frisbee slider. Maybe it has to do with the fact that he’s abandoned the cutter and is now throwing more four-seamers than sinkers (prior to 2021, the last time Ottavino had used his four-seamer more than 20% of the time was in 2017). Maybe — the spin of his slider mirrors the spin of his sinker and not his four-seamer — but it doesn’t explain why there’s been a continuous decline.

There is one change that tracks with the decreasing strikeouts, though. Correlation doesn’t equal causation, but check this out. On the left is Ottavino on the mound in 2018, and on the right is a screenshot from last season:

Over the past few seasons, Ottavino has gradually moved towards the first-base side of the mound, and looking at stills of his delivery, it seems like the new version produces a more straightforward path to home plate than before. His signature crossfire motion is subdued. You’d think that the image on the right represents a more efficient and streamlined delivery, but perhaps Ottavino’s old mechanics granted him a better feel for the slider. It’s tough to say. But there’s likely another fantastic season left inside him, and it would benefit the Mets greatly to unlock it.

Cardinals Sign Nick Wittgren

Closing out our reliever roundup in Nick Wittgren, who signed a one-year, $1.2 million deal with the Cardinals after a miserable year in Cleveland (-0.3 WAR). And while that seems like a salient red flag, it’s also seems unlikely that he’ll be anywhere near as bad in the future. First, Wittgren was the victim of a high HR/FB rate (24.5%) that he in no way deserved. Second, he probably should have been rewarded with a higher strikeout rate. Despite upping his swinging strike rate, Wittgren recorded a lower strikeout rate in 2021 than he did two years prior. Lastly, owing to his solid control, he’s walked less than 7% of batters faced since arriving in Cleveland. All in all, expect him to quietly log 50-or-so innings of low-4 FIP ball. That’s a result any team would gladly take.