Every contending team dreams of that one lefty in the bullpen who can flip the switch late in a game - the kind of arm that neutralizes elite hitters, no matter which side of the plate they stand on. For Team USA, heading into the 2026 World Baseball Classic, that guy is Gabe Speier. And make no mistake, he’s not just filling a roster spot - he’s bringing a weaponized arm slot and a sharp arsenal to what’s shaping up to be a stacked American pitching staff.
Speier, the Mariners’ sidearming southpaw, is the only true left-handed reliever currently on the U.S. roster (unless you want to count Clayton Kershaw, which, at this point, is more ceremonial than tactical). That distinction could make Speier a key figure in high-leverage moments, especially as Team USA builds around reigning Cy Young winners Tarik Skubal and Paul Skenes.
So how did Speier go from bullpen depth to potential difference-maker on the global stage? Let’s break it down.
1. Elite Strikeout-to-Walk Numbers That Stack Up With the Game’s Best
Speier’s rise in Seattle hasn’t been quiet - at least not if you’re paying attention to the numbers. Since joining the Mariners, he's struck out 31.8% of batters he’s faced, a top-20 mark among relievers with similar workloads over the past three seasons. That kind of swing-and-miss stuff has always been in his toolkit, but 2025 is when everything clicked.
In 2024, Speier’s ERA ballooned to 5.70 - a rough ride, despite a solid strikeout rate. But in 2025, he didn’t just bounce back - he dominated, slashing his ERA by more than three runs to a stingy 2.61.
The difference? Command.
Speier didn’t just keep the strikeouts coming; he cut his walk rate to a career-low 4.5%, while bumping his K-rate to a career-high 33.7%. That’s a rare combo, and it put him in elite company. Only a handful of relievers in the league posted a bigger gap between strikeout and walk rates - a list that includes names like Mason Miller, Aroldis Chapman, and Edwin Díaz.
Let’s look at the leaderboard:
Relievers with largest K%-BB% gap in 2025 (min. 50 IP):
- Mason Miller - 32.5%
- Aroldis Chapman - 30.7%
- Edwin Díaz - 29.8%
- Gabe Speier - 29.2%
- Josh Hader - 29.1%
That kind of efficiency - missing bats without giving away free passes - is how you win late-inning battles in tournament play.
And the advanced metrics back it up. According to Statcast’s expected ERA (xERA), which blends strikeouts, walks, and quality of contact, Speier belonged among the league’s most effective arms in 2025:
Lowest xERA, 2025 (min. 100 batters faced): 1.
Josh Hader - 2.00
2.
Aroldis Chapman - 2.11
3.
Brandon Woodruff - 2.22
T-4.
Gabe Speier - 2.49
T-4.
Edwin Díaz - 2.49
T-4.
Zack Wheeler - 2.49
T-4.
Caleb Thielbar - 2.49
Bottom line: Speier didn’t just get lucky. The numbers say he earned every bit of that sub-3.00 ERA - and then some.
2. A Three-Pitch Mix With Purpose
Speier doesn’t overpower hitters with triple-digit heat, but he doesn’t need to. His success comes from a carefully crafted pitch mix - one that plays off his deceptive arm slot and allows him to attack hitters from both sides of the plate.
Here’s what he’s working with:
- Four-seam fastball (95 mph)
- Sinker (94 mph)
- Slider (83 mph)
The four-seamer and sinker are his control pitches - he fills up the zone with both. Against right-handers, he elevates the four-seam fastball to generate whiffs. Against lefties, he busts them inside with the sinker, which runs in hard and jams them up.
That four-seamer is a sneaky weapon. Right-handed hitters whiffed on it 27% of the time in 2025 - well above league average for lefty pitchers in that matchup. It’s how Speier neutralizes the platoon disadvantage.
The sinker, on the other hand, is all about soft contact. It doesn’t miss a ton of bats, but it doesn’t have to.
It runs 18 inches in on lefties, making it nearly impossible to square up. The result?
Hitters can’t pull the ball in the air - the zone where most of the damage happens.
Only 10% of batted balls off Speier last season were pulled in the air. Against lefties?
Just 9%. That’s elite contact management, and it all starts with the sinker setting the tone.
Then there’s the slider - Speier’s true out pitch. With sharp vertical drop (about four inches more than the average lefty slider), it’s a chase machine.
He throws it to both sides of the plate, and hitters can’t resist. Speier landed his fastballs in the zone over 60% of the time last year, which forced hitters to honor the zone - and opened the door for the slider to do its thing.
The proof is in the numbers:
- Chase rate: 36% (98th percentile in MLB)
- Whiff rate on slider: 49%
When Speier gets to two strikes, that slider becomes a problem - and hitters haven’t found the answer.
3. He’s Built to Face Shohei Ohtani
Let’s talk matchups - because in a tournament like the World Baseball Classic, it often comes down to one at-bat in one inning against one generational hitter. And if Team USA ends up facing Japan again, someone’s going to have to deal with Shohei Ohtani.
Gabe Speier might be that guy.
Just look back at October. The Phillies’ bullpen, loaded with low-slot lefties like Cristopher Sánchez, Ranger Suárez, Jesús Luzardo, Matt Strahm and Tanner Banks, held Ohtani to one hit in 16 at-bats in the NLDS - striking him out eight times.
The common thread? Arm angle and sink.
Sánchez, in particular, gave Ohtani fits with heavy sinkers running in on his hands. That’s exactly the kind of pitch Speier thrives on.
In fact, his 28-degree arm angle is even lower than those Phillies lefties, and his sinker - just like Sánchez’s - averages 18 inches of horizontal movement. It’s tailor-made to jam Ohtani and take away his power zone.
So if the U.S. finds itself in a late-inning showdown with Japan’s biggest bat, they’ve got a specialist ready. Speier’s not just a lefty - he’s the kind of lefty who’s built to neutralize the best.
Final Word
Gabe Speier might not be the flashiest name on Team USA’s roster, but he could end up being one of the most important. With elite command, a deceptive delivery, and a pitch mix that plays against anyone - especially lefty power threats - Speier gives the U.S. bullpen a versatile, high-leverage weapon.
He’s earned this spot. And when the tournament heats up, don’t be surprised if he’s the one getting the ball with the game on the line.