Every great team can use a sidearming lefty in its bullpen. And out of all the sidearming lefties, Team USA picked the Mariners' for the World Baseball Classic. For good reason.
Gabe Speier is set to pitch in the 2026 Classic as of this week, making him the only true left-handed reliever on the U.S. roster so far (unless you count Clayton Kershaw). That sets up Speier to play a key role in the tournament, as the United States tries to finish assembling an all-world pitching staff led by both reigning Cy Young winners, Tarik Skubal and Paul Skenes.
Speier has earned that role after a 2025 season in which he was one of the best lockdown relievers in the Majors -- lefty or otherwise. Speier was a nightmare against left-handed hitters last season … but he was also a nightmare against right-handed hitters.
Here are three reasons Team USA wants Speier pitching out of its bullpen in the 2026 World Baseball Classic.
1) His strikeout-to-walk numbers are elite
Speier has boasted elite strikeout rates ever since he got to Seattle -- he's struck out 31.8% of the batters he's faced as a Mariner, which is a top-20 mark for pitchers who've thrown as many innings as him over the last three seasons.
But in 2024, his ERA was 5.70. In 2025, he lowered it by over three runs to 2.61. He was striking out tons of batters in both seasons. So what changed?
His command. Speier started locating his pitches way better last season. That let him keep up his K's while also cutting way down on his free passes.
Even as he posted a career-high 33.7% strikeout rate, Speier also posted a career-low 4.5% walk rate. Both of those ranked near the top of the league on their own -- Speier was in the top 5% of Major League pitchers in both categories -- but the combination is what really makes Speier stand out.
The gap between Speier's strikeout rate and walk rate, 29.2 percentage points, was one of the largest for any reliever in the Majors. Speier is in the middle of the best closers in baseball, including his Team USA teammate Mason Miller.
RP with largest gap between K% and BB%, 2025
Min. 50 innings pitched
- 1. Mason Miller: 32.5%
- 2. Aroldis Chapman: 30.7%
- 3. Edwin Díaz: 29.8%
- 4. Gabe Speier: 29.2%
- 5. Josh Hader: 29.1%
When a pitcher strikes out that many people and walks so few people, he's just not going to give up many runs.
To that end, Speier's expected ERA, according to Statcast, was among the MLB leaders for 2025. Expected ERA combines a pitcher's strikeouts, walks and quality of contact allowed to measure what his ERA deserves to look like.
Lowest xERA, 2025
Min. 100 batters faced
- 1. Josh Hader: 2.00
- 2. Aroldis Chapman: 2.11
- 3. Brandon Woodruff: 2.22
- 4-T. Gabe Speier: 2.49
- 4-T. Edwin Díaz: 2.49
- 4-T. Zack Wheeler: 2.49
- 4-T. Caleb Thielbar: 2.49
That number tells you Speier chopping three runs off his real ERA last year was no fluke.
2) Every pitch in his arsenal serves a purpose
Speier throws three pitches: a 95 mph four-seam fastball, a 94 mph sinker and an 83 mph slider. He was able to execute those three pitches exactly how he wanted to in 2025.
Speier uses his four-seamer and sinker to pound the strike zone. He attacks right-handed hitters with four-seamers at the top of the zone, and jams left-handed hitters with sinkers up and in.
The four-seamer is a swing-and-miss pitch that helps Speier neutralize the platoon advantage a righty holds over him. Speier's four-seamer generated a 27% whiff rate from right-handed hitters last season, much higher than the average big league lefty in the same matchup (just under 21%).
The sinker, by contrast, is a pitch designed to force poor contact in lefty-lefty matchups. It barely gets any whiffs or strikeouts, but it doesn't need to. By busting lefties inside with a sinker that runs 18 inches in on their hands, Speier makes it very hard for them to get the barrel on the ball -- while also stopping them from leaning out over the plate to cheat against a four-seamer or slider away.
Only about 10% of the batted balls against Speier last season were pulled in the air, including only 9% of his batted balls allowed to lefties. Pulled air contact tends to be where hitters do damage, and Speier stopped them from doing it. That all starts with his sinker.
Both of Speier's fastballs help set up his slider as a chase pitch. Speier landed both his four-seamer and sinker in the strike zone over 60% of the time last season, and all those fastball strikes make it harder for hitters to lay off the sliders that break down underneath them.
Speier's slider gets sharp vertical movement -- it drops about four inches more than the average lefty slider -- and he can snap it off to righties or lefties. The slider is the biggest reason Speier ranked in the 98th percentile of MLB pitchers with a 36% chase rate induced last season.
And hitters aren't making contact with Speier's slider when it's in the dead zones he likes to throw it to. He generated a 49% whiff rate on the slider in 2025.
3) He can be the Ohtani specialist
If history repeats itself in the 2026 World Baseball Classic, Team USA could be in for a rematch with Japan. And that would mean somebody has to get out Shohei Ohtani in the late innings.
Speier can be that guy. He's the exact type of pitcher that the Phillies used to shut down Ohtani in their playoff series in October: a low arm angle lefty with a heavy sinker.
The Phillies' southpaws -- Cristopher Sánchez, Ranger Suárez, Jesús Luzardo, Matt Strahm and Tanner Banks -- held Ohtani to one hit in 16 at-bats with eight strikeouts in the NLDS. All but Banks (who only pitched to Ohtani once) have the more sidearm style delivery that Ohtani struggles with. And Sánchez in particular gave Ohtani fits with heavy sinkers in on his hands.
Which brings us back to Speier -- who's even more of a sidearmer (his 28 degree arm angle is lower than all those Phillies), and whose sinker, like Sánchez's, gets a ton of horizontal movement (both average 18 inches) and is his No. 1 pitch against lefties. If Speier faced Ohtani in the World Baseball Classic, he could attack him the same way Sánchez and the Phillies did in the MLB postseason.
Now, it's not like Team USA is building its bullpen to get out one guy. But Ohtani isn't the only superstar lefty slugger whose skill set Speier can neutralize. He should match up with plenty of great hitters on the other teams in the Classic, too.