The Los Angeles Dodgers are the defending World Series champions and current odds-on favorites to hoist the trophy again in 2025. They added two of the most high-profile pitching free agents this offseason when they signed Blake Snell and Roki Sasaki. Yet, for all of their big names and having the second-best record in the National League, the pitcher that has emerged as a key cog in this potential title run is rookie reliever Ben Casparius.
Now, Casparius isn't a reliever by trade. The 26-year-old pitched in 21 games in the minor leagues last season, and 19 of them were starts. And pretty good starts too. In his 88.2 innings split between Double-A and Triple-A last year, Casparius posted a 3.35 ERA, 1.25 WHIP, and 106/46 K/BB ratio. However, when the Dodgers' starting pitching depth started to dry up, and they needed a little more length out of their bullpen, they turned to Casparius.
After making his two relief appearances in Triple-A, he was promoted to the big league roster and pitched 8.1 solid innings over three appearances for the Dodgers in the final weeks of the season. While he initially believed he would come into the 2025 season as a starter, he was, yet again, thrust into a hybrid role in the bullpen to help the team navigate starting pitcher injuries.
"It's about not ever getting too comfortable in a certain situation," Casparius explained before the series finale against the Mets last weekend. "That's the biggest key, just the preparation being pretty similar day to day, whether I'm starting the game, coming in the ninth inning, eighth inning, throwing innings four through six, whatever that might be...It's just being able to be thrown into different situations and not necessarily give it a label. Obviously, I'm a reliever by trade right now, and it's something that I'm completely fine with, being able to help the team as much as possible in whatever they need."
What the Dodgers need in 2025 is depth from their bullpen. Injuries to Snell, Tyler Glasnow, Gavin Stone, and Emmet Sheehan, plus Shoehi Ohtani not yet being able to pitch mean that Dustin May, Clayton Kershaw and Tony Gonsolin have all been thrust into spots in the starting rotation despite barely pitching in 2024. With the Dodgers being cautious of how deep any of those pitchers can go in a given game, they have frequently needed multiple-inning appearances from their relievers throughout the week. Something that has been a common occurrence for the Dodgers in recent years with all their pitching injuries.
"It's kind of a similar story to last year," recalled Casparius. "I wasn't a part of it until mid-August, but just the versatility that needs to happen in order to get through games with some of the injuries we've been having. You know, be able to step up and fill a role where it's not necessarily anything set in stone. It's a little bit more chaotic. But I've really just bought into that. I enjoy it. It's been great. I feel like I'm in a good spot."
There's no question that Casparius is in a good spot. He has pitched 35.1 innings in 18 appearances this year, posting a 2.80 ERA, 0.93 WHIP, and 41/6 K/BB ratio. He has recorded an impressive 15% swinging strike rate and allowed just a 27% hard-hit rate on the season.
While Casparius has had success in the minor leagues, some of his level of production this season can be attributed to a mechanical change he made in the off-season, raising his arm angle from 42 degrees to 47 degrees, which is a pretty drastic change.
"It was a feel thing," he explained about raising his arm slot. "I honestly didn't look at any metrics in terms of release height or extension or anything like that, leading up to spring training. I think it was more optimizing. For me, it's "smooth is fast," and trying not to get robotic or force deeper positions. It's more just thinking, 'Let's be fluid and when it's time to turn on the jets at the very last second, that's when it is.' I think it's just forcing me to stay upright a little bit longer, or at least get over the top of my throw a little bit longer."
That mechanical change has led to some shifts in Casparius' pitch shapes, including his cutter, which added almost 2.5 inches of horizontal movement and slightly more "rise" as it approaches the plate.
"I would say [the movement change is due to] arm slot," admitted Casparius. "I think the conviction of the pitch is definitely higher too. I'm not necessarily trying to shape it. I'm kind of letting the grip take care of itself."
That added confidence in the cutter has led to Casparius using it 21% of the time in 2025, as opposed to just 4% in his small sample in 2024. Last year, he didn't throw a single cutter to right-handed hitters at the MLB level, but he's now using it nearly 16% of the time, primarily attacking the outside part of the plate with it and using it to set up his slider for swinging strikes.
"To put it simply, I think [the cutter] is just my pitch that I am in the zone a lot with that's not a fastball, you know? It's just another option that I'm throwing more in the zone than I am my fastball, and it's not straight. These guys can all hit fastballs. If it's a day where I'm leaving my curveball a little bit arm-side, or I'm pulling off the slider a little bit, it's just another option where it's something in the zone that's got a little bit of movement to it. Traditionally, it's a soft contact type pitch, not necessarily a swing and miss. I've had a few outings this year where I've gone out there and thrown a few cutters, and you're looking at a five or six-pitch inning."
True to his word, Casparius' cutter has allowed just a 28% Ideal Contact Rate, which is the 85th percentile in baseball. It has just a .194 batting average against with a .223 wOBA and 83 mph average exit velocity. However, it has also missed bats, primarily to lefties, with a 20.3% swinging strike rate on the season. Part of that success is because Casparius does a good job of jamming lefties inside with his cutter and running it off the plate after he attacks inside with a four-seam fastball that has also changed shape in 2025.
The higher arm slot has caused Casparius' four-seamer to jump from 15 inches of Induced Vertical Break (iVB) to 18.1 inches of iVB while cutting almost two inches of horizontal movement. That means his four-seamer appears to "rise" more as it approaches home plate, fighting gravity and becoming a flatter pitch.
"I think it's because of the mechanical change," guessed Casparius. "Also, in Double-A, you're using a different ball, so the metrics are going to be inflated with the ball they're using. And then in Triple-A, that was the first time I had used the big league ball in a long time, so I think, just getting more comfortable with it takes time. I don't think there's anybody who makes the switch that quickly, and it's like, "Oh, my stuff is in a really good spot." You kind of have to figure that out. Being a little bit more north-south this year, with a higher arm slot, is helping me to stay behind the fastball."
That added vertical movement on the fastball also means that it should succeed more up in the zone than it had in the past. A flatter fastball drops less with gravity as it approaches the plate. That gives it the sensation that it's rising as it approaches the batter, so when those types of fastballs are thrown up in the zone, it's very easy for a hitter to swing underneath it.
Casparius has a 20% swinging strike rate on his four-seamer to lefties this season in part because he uses it up in the zone 65% of the time to them. However, he throws it up in the zone just 45% of the time to righties, and his swinging strike rate to them on the four-seamer is a little over 16%. Both are still above league average, but the pitch has been a little more successful as a two-strike pitch to lefties this season.
"We have very advanced reports on every guy," explained Casparius. "So, for my arsenal, this is how I'm gonna typically attack this type of hitter, or this lefty handles off-speed in the zone well, so we need to do this. "I think it's more of a matchup type thing. There are certain teams that are going to hunt fastballs up in the zone more than they are down, where I can get away with throwing some fastballs down in the zone. So I think it just bounces from approach to approach, and a team philosophy for what they're trying to do."
Those types of strategic adjustments are something that Casparius is continuing to learn as he shifts his focus from being a starting pitcher to being a reliever.
"I think the relief side of things has helped with some of my starts too, in just focusing on one pitch at a time and not projecting or looking ahead towards the next inning, or who I have to face if I walk this guy. It's just gotten me into a mindset of, every inning here's my best stuff. Attack guys. Mix it up. Don't be too predictable. Just being able to go out there and trust everything has really helped me with every single role."
Yet, the role that Casparius still longs to fill one day is that of MLB starter: "At some point, I do think that I have the durability and the arsenal to be an effective starting pitcher, but it just depends on what the team needs at the right time."
If the Dodgers do eventually give Casparius a chance to operate as a more traditional starter, the right-hander knows that will mean adapting from the approach that's currently allowing him to have so much success.
"When there were conversations about potentially moving back into the rotation. It was like, "Hey, how do we tease the inside part of the plate?" First time, second time, third even, you can get away with some stuff. But, you know, they're the best hitters in the world. They're here for a reason. They make adjustments on the fly, so it's something that was in discussions about how we can utilize the inner half too."
On the season, Casparius is throwing inside to right-handed hitters just 15.8% of the time. Much of that has to do with an arsenal that is dominated by a slider, cutter, and four-seam fastball, but it's also the luxury of not having to attack all quadrants of the plate when you only face a hitter one time. Starters don't have that luxury, which is why, for comparison's sake, his teammate Yoshinobu Yamamoto throws inside to right-handed hitters 33% of the time, and Dustin May throws inside to righties 39% of the time
"Traditionally, I think starting pitchers do a good job of utilizing the inside part of the plate or at least showing that they can get it in there to open up what works away pretty well," admitted Casparius. "The attack plan would be a little bit different [as a starter]. It's, 'Hey, we're gonna go six innings here. I'm probably facing at least part of the lineup three times through,' and that's where you need to potentially back-pocket a pitch. Guys that are able to go off the book a little bit, be unique, and maybe throw some stuff that you don't necessarily throw a lot to a certain type of guy. I think once you can go off script a little bit and be comfortable with that, it's when you can find when you can find some success."
That could mean that Casparius simply utilizes the fastball inside more often. It could also mean attacking the inside part of the plate with a pretty north-south curveball that he has already thrown inside 61% of the time to righties in a small sample size. But all of those adjustments remain a challenge for another day. For now, Casparius remains a key cog in the Dodgers' bullpen, and that's more than enough for him.
"I want to win here, and whether it's what I'm doing right now, if it's in the rotation, whatever it is, I'm cool with it. At the end of the day, it's whatever gives the team the best chance to win, and best chance to win over the course of a season."
