Angels Make a Move, Ink Robert Stephenson

Nathan Ray Seebeck-USA TODAY Sports

The first two months of the offseason were entirely defined by one player: Shohei Ohtani. The two-way star’s departure for (the actual city of) Los Angeles had a particularly meaningful effect on his former club, which is in need of some major moves to be remotely competitive in his absence. To fill the Ohtani-sized hole on the roster, the Angels have signed… a 37-year old reliever, two different sidearmers named Adam, and a hurler whose claim to fame is having suffered multiple self-inflicted injuries as a result of frustration. In spite of these lackluster additions, ZiPS views this team rather favorably given the circumstances – nowhere near title favorites, but not complete embarrassments either. And while none of the relievers they’ve added thus far will really move the needle in either direction, their latest signing adds a significant high-leverage arm to the mix, with righty Robert Stephenson inking a three-year deal worth $33 million to come to Anaheim.

Stephenson’s career prior to hitting free agency was, in a word, inconsistent. The Reds brought him up as a starter whose control issues pushed him to the ‘pen; since then he’s dealt with persistent home run issues, perhaps expected from a fly ball-heavy pitcher who’s played in Cincinnati and Colorado. But flashes of excellent stuff were always there, including a 2019 campaign where he ranked third among all relievers in swinging strike rate. When he thrived, he did so thanks to an absolute beauty of a slider, thrown with sharp, downward bite. While the fastball was often hammered with ease, his breaking ball ran a career whiff rate north of 45%. He threw it over half the time with the Reds and Pirates (but not the Rockies, because of course not). In an alternate universe, Stephenson could have played out the year in Pittsburgh before hitting the open market as just another faceless middle reliever. But in early June, a Tampa Bay Rays team in dire need of reinforcements came calling for his services, and he did this:

Robert Stephenson as a Ray
Statistic Value Ranking
O-Swing% 47.2% 1st
Z-Whiff% 31% 2nd
SwStr% 28.9% 1st
K-BB% 37.6% 2nd
xwOBA .217 1st
SIERA 1.78 1st
Rankings are out of 188 qualified pitchers

The Rays didn’t just improve Stephenson, they turned him into the best reliever in baseball. These numbers are absurd outliers, especially his swinging strike rate, which bested second-place Félix Bautista by nearly eight percentage points. He commanded the zone like no other, getting hitters to swing at everything while coming up empty on meaty strikes. The Rays getting the most out of every reliever with a pulse feels like a tired narrative at this point, but they continue to churn out arms at an impressive rate despite advances in development and scouting by the rest of the league. And their work with Stephenson might be the most Rays-ian, unorthodox move possible.

Often times, pitch arsenals are the low-hanging fruit that savvy teams can pluck (or rather, tweak) to their advantage. The Rays have been ahead of the curve in the league-wide trend of throwing fewer fastballs, and the stories of their pitchers crafting new pitches, especially sliders, are plentiful. They’ve also embraced (or kickstarted) the rise of the sweeper, throwing the fourth-most of any team in the Statcast era while chasing down pitchers with outlier release points that contribute to horizontal movement. Given their tendencies, maybe they would delete Stephenson’s fastball in a Matt Wisler-esque move, or turn his regular slider into a whirly. Instead, they went in the opposite direction in pitch movement, opting to transform Stephenson’s slider into a harder cutter:

Robert Stephenson’s Revamped Pitch Mix
Pitch Type With Pirates With Rays
Slider 64% 7%
Cutter 0% 60%
Four-Seam 31% 20%
Splitter 5% 13%
SOURCE: Baseball Savant

Literally overnight, Stephenson learned a new pitch and ascended to elite status on its back. His new primary pitch sacrificed almost all of its horizontal movement for increased velocity, relying on the pitch’s relative lack of movement compared to other fastballs to catch hitters off guard. By season’s end, he ranked third in cutter pitch value, behind two starters with 1,786 and 693 cutters thrown; Stephenson had just 316. With its four-tick increase in velocity over the old slider, his retooled cutter more closely resembled his fastball out of the hand, preventing hitters from waiting for a hanging slider and giving them less time to react.

Stephenson also commanded his cutter far better than his slider. He landed both pitches in the zone at a similar rate, but he wasted far fewer cutters and consistently located them right underneath the zone for chases and misses. When opposing hitters saw a cutter off the plate, they still swung over half the time and with poor results; Stephenson was one of just three pitchers to generate positive run value in the “chase” area of the zone. ZiPS is fully bought in on Stephenson’s adjustments and forecasts a low-three ERA with a strikeout rate around 32%, which is impressive even if it’s not at the earth-shattering level he reached last season.

We haven’t really checked in on the state of the Angels’ roster this offseason, though it’s not like they’ve given us many reasons to. For this pitching staff, which has only made marginal upgrades until now, 2024 will be a critical year in determining whether they can succeed in Ohtani’s absence. Because of his classification as a two-way player, the Angels have been allowed an extra pitcher on their roster over the past three years, enabling them to keep a fully stocked bullpen while running a six-man rotation. While RosterResource currently projects them to go back to a five-man system, there are workload concerns with this transition. None of their homegrown starters have ever made 30 starts in a season, and only Tyler Anderson has ever qualified for the ERA title.

With that in mind, it makes sense for the team to have taken a quantity-over-quality approach to adding bullpen arms, anticipating a need for any warm bodies who can slot in during the season. In addition to the nine pitchers who are on the 40-man roster but not projected to break camp, the Angels will be expecting former closer José Quijada to make a midseason return from Tommy John surgery and could have other rookies waiting in the wings from their all-pitcher draft three seasons ago. But an abundance of arms is no guarantee of success. Prior to Stephenson’s signing, no Angel reliever had a projected ERA- of 95 or better; the Rays, on the other hand, have nine such arms.

Prior to the 2022 season, the Angels inked three relievers to multi-year contracts with the hope of elevating a staff that had ranked 23rd in ERA- the year prior. Two years later, Aaron Loup and Ryan Tepera were each designated for assignment following uninspiring tenures, while star closer Raisel Iglesias was traded away functionally for free in a cost-cutting move. Since then, their relief corps has only gotten worse, bottoming out last season with a collective 4.88 ERA and 0.6 WAR. For this team to remotely sniff success in the near future, they’ll need to quickly rebuild in an area they’ve been bleeding value for the better part of a decade. And Stephenson, the best reliever left on the market, is a solid place to start.

Kyle is a FanGraphs contributor who likes to write about unique players who aren't superstars. He likes multipositional catchers, dislikes fastballs, and wants to see the return of the 100-inning reliever. He's currently a college student studying math education, and wants to apply that experience to his writing by making sabermetrics more accessible to learn about. Previously, he's written for PitcherList using pitch data to bring analytical insight to pitcher GIFs and on his personal blog about the Angels.

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3 months ago

Robert Stephenson should only be allowed to pitch for the Pirates.

Giant Slormember
3 months ago
Reply to  MikeS

Rays’ pitching lab got him to tap into his Mr Hyde — free the monster.