When I first heard that the Mariners were honoring the best left-handed pitcher in baseball history, naturally I assumed they were unveiling some sort of Gabe Speier promotion. Turns out they are retiring Randy Johnson’s number. But you can understand my confusion: This year, Speier has a lower ERA and a higher strikeout rate than Johnson ever did with Seattle.

I open with this psuedo-joke not to detract from Johnson, whose legacy the Mariners are long overdue in acknowledging, but to illustrate just how dominant Gabe Speier has been this year. It’s a welcome bounceback that was on full display in Speier’s most recent outing, when he struck out four of the six Minnesota Twins he faced, punctuated by this pie in the face to Carlos Correa.

When the Mariners first acquired Speier off waivers in November of 2022, expectations were modest. Over an on-again, off-again relationship with the big league squad in Kansas City’s organization, he’d tossed 40 innings with a 3.83 ERA and 4.23 FIP, striking out 20.2% of batters while walking 8.7% of them. That’s an MLB-caliber player, but not a stalwart of a bullpen’s A side.

The Mariners were quick to seize on where they thought he could improve. In his first phone call with pitching coach Pete Woodward, Woody told Speier that his sinker is his best pitch and recommended replacing some of his four-seamers to lefties with sinkers running in. Speier says, “I think with Kansas City, I was just kind of finding my way. And then I came here, and they kind of gave me a blueprint of what to do and what to focus on, and I just accepted it as my identity as a pitcher.” It worked.

Leaning mostly on that one change, Speier had a breakout year, more than doubling his K% – BB% from 11.6% during his Royals tenure to 24.5% with the Mariners in 2023. The key metric underpinning that success was his first-in-MLB first-pitch strike rate. He started in an 0-1 count 78.2% of the time, which was not just the best, but the best by a decent margin. By working ahead essentially all the time, he was able to get hitters to chase, inducing swings on pitches outside the strike zone more often than 548 of the 549 other guys to pitch at least 20 innings.

It was hard to expect that he’d be quite as good in 2024, just based on the laws of mean-regression, but few saw a total collapse coming. Yet that’s what happened. He stopped working ahead, stopped getting guys to chase, and his walk rate ballooned. But the most alarming stat was his velocity, which dropped from 95.1 mph in 2023 to 93.5 mph in early 2024.

It would turn out that the velo dip was caused by an injury. Speier had a grade two strain in the subscapularis, which is a muscle that’s part of all the spaghetti going on in your shoulder. It sits underneath the shoulder blade and helps connect the humerus (the upper arm bone) with the capsule of the ball-and-socket that is the shoulder joint itself. When you think about what that muscle does, and learn that Speier’s was torn 50% of the way through, you wonder less how his ERA spiked to 5.70 and more how he was able to throw a baseball at all.

Amazingly, he says he didn’t feel the tear in April of last year. And while his velocity was down a tick from 2023 that month, it was April, so who’s going to make too much of a velocity decline that early? But eventually it got to a point where it was “like, really painful,” so the Mariners took an MRI. That’s when they discovered the tear, and Speier hit the IL. The wound healed and he returned in late summer, but rather than coming back, the velocity deteriorated further, and the results with it.

Luckily, Speier was able to spend this offseason resting and then training to get his velo back. It’s hard not to conclude that at least part of the issue was mental. “When you have a dip in velo like that, there are definitely thoughts of ‘Is it going to come back?’”

So when he was clocked at 96 this spring, “that was a big, big weight lifted off the shoulders.” (Lookout Landing regrettably neglected to ask if that pun was intentional, but Speier went to a really good high school, so let’s assume it was.) He’s carried both the velocity and the mentality into the regular season. “When you know you’re pitching with your best stuff, it’s easy to pitch with confidence.”

That’s taken him back to the top of the charts. His first-pitch strike rate? Back up to 77.0%, second out of 328. Chase rate? Back up to 39.5%, ninth in baseball.

But in many ways, he’s not just back to where he was in 2023, he’s exceeding it. As the only southpaw on the Mariners’ pitching staff, he’s often called in for a lefty pocket of an opposing lineup. But his stats against righties have caught up this year too. He notes, “I always had a Plan A against lefties, and with righties, not as much. [This year,] I’ve really just come up with a plan for righties and really sticking to it and gaining confidence.”

Key to that plan seems to be replacing sinkers with four-seamers when facing hitters of the righty persuasion. That makes sense, since while the sinker is devastating to lefties, the opposite has been true against righties. This isn’t true for every pitcher, but in general, horizontal movement is more effective when facing same-handed batters. This year, he’s letting the good carry on his four-seamer cook, and righties are whiffing on it twice for every five swings. That does even more to set up his slider, which Speier is dotting with pinpoint precision, like in that strikeout to Correa up above.

So in 2025, his overall numbers have spiked to something resembling an All-Star. Opposing hitters are making contact on fewer than two thirds of their swings, the 11th-best mark in baseball, and he now leads all of baseball in the percentage of his pitches that end with a called strike or a whiff, at 37%. And he’s doing that with a career-low walk rate, just 4.6%.

On the rare occasions when hitters manage to put a ball in play, they’re killing worms more than half the time, a figure in the top 15% in MLB.

It’s the deadliest combination a pitcher can have: high strikeouts, low walks, bad contact. Truly, what more can you ask for? The only other pitcher in baseball with at least 20 IP who has both a K% – BB% greater than 30% and a GB% better than 50% is Logan Gilbert.

The Speier Choir might have been singing songs in a minor key last year, but in 2025, it’s been nothing but odes to joy.