The most unhittable arm in the minors is a 24-year-old lefty reliever. Two months ago, he was selected as a player to be named later in a major-league trade swung in February. He’s never made a prospect list of any significance, be it league-wide or organizational, and he doesn’t have any video clips on the official Minor League Baseball website. Whenever we write posts here, we’re supposed to include photos to go out to accompany the tweets, and I had to use a photo of the player from his previous club. I didn’t even know how to pronounce the guy’s last name until this morning.

The most unhittable arm in the minors is Colin Poche. Last year, he led the minor leagues in strikeout rate. This year, he again leads the minor leagues in strikeout rate, having increased his own strikeout rate by a dozen points despite going up against much stiffer competition. When Poche pitched in High-A last year, he struck out 37% of the hitters. In Double-A this year, he struck out 60% of the hitters. In Triple-A this year, he’s struck out 50% of the hitters. All year long, over 41.1 innings, he’s allowed just three runs. He’s allowed an OBP of .185, and he’s allowed a slugging percentage of .184. Colin Poche is turning in one of the most unbelievable performances you might ever see. Better still, it’s not entirely clear how he’s doing it.

Eric Longenhagen recently got a chance to watch Poche pitch. I’ll just excerpt the entirety of what he wrote:

Poche sits just 89-92 and has an above-average breaking ball. He reaches back for 94 at times, but on paper that looks like an up-and-down reliever. Somehow, Poche’s fastball makes hitters very uncomfortable and produces an elite swinging-strike rate. He has 78 strikeouts in just over 40 innings this year at Double- and Triple-A. He was acquired from Arizona as one of the PTBNL in the Souza deal, but a 2018 debut would require a 40-man alteration.

As a player, Poche is now Rays property, having been plucked from the Diamondbacks. At first, the Rays kept Poche in Double-A — when he was traded, he just had to walk to the stadium’s other clubhouse — but after three appearances, Poche was promoted to the International League. He’s continued to dominate, and he’s done so over multi-inning outings. Poche has gotten up to 55 pitches, and he’s twice been used as a Triple-A “opener.” While the Rays have an awfully crowded 40-man roster, Poche is putting himself in position to debut. And his stuff is still just…fine. The breaking ball is useful, and the fastball isn’t slow, but the explanation here appears to be a matter of deception. Poche himself would agree with that:

Poche’s fastball doesn’t light up radar guns, usually staying around 92-93 mph. But it appears much faster to hitters because of the way he hides the ball on his load and then aggressively takes a long stride to the plate. “I’ve always thrown that way,” he said. “Even when I was young and throwing slow, I was getting it by people.”

Poche doesn’t have a particularly funky delivery. There just has to be something about his arm action. We can get back into that a little later. For now, let’s play with some data. I think of Double-A and Triple-A as representing the high minors. So, here are all Double-A and Triple-A pitchers this year, displayed by their walks and strikeouts. Poche’s is the dot in yellow.

Out of the pool, Poche has the highest strikeout rate, by seven points. He has the highest K-BB%, by nine points. It’s clear that Poche is doing something exceptional. Let’s now expand the data set. FanGraphs has minor-league information stretching back to 2006. So here are all minor-league pitchers since 2006, split by season, with a minimum of at least 40 innings. This is no longer just Double-A and Triple-A; this is all levels. In yellow, you see 2018 Poche. In red, you see 2017 Poche.

It’s rare for a player to improve upon an extreme data point, given that forces typically conspire to bring extreme data points back to earth. Still, Poche continues to stand out. His current season is even more impressive than the last one. I know it’s not entirely fair to compare, since the 2018 season isn’t actually finished, but I’m just trying to get a point across. To give you some perspective. Here are the highest K-BB% marks since 2006, showing minor-league pitchers and their levels:

Dayton might be the most appropriate comparison. And not just because he’s left-handed. I know his career has been derailed due to injury, but Dayton dominated in 2016 with a low-90s fastball, and he took that domination with him into the bigs. Down the stretch, Dayton became one of the Dodgers’ more trusted relievers. Pitchers break, but Dayton was still some proof of concept. And it’s not as if his career is all done.

It took me a long time to try to find any half-decent Poche video. I had to go back to spring training, when Poche relieved a few times with the Diamondbacks. Here, then, are four fastballs, with the camera observing from an unfortunate angle. Nothing I can do. Fastball No. 1:

Fastball No. 2:

Fastball No. 3:

Fastball No. 4:

As the deception goes, my guess is that Poche must keep the ball hidden behind his head and elbow right up until release. That would be the old Yusmeiro Petit “invisi-ball” trick. And given both Poche’s arm slot and fly-ball tendencies, I assume he has one of those rising fastballs, one of those fastballs that stays above the barrel. The Rays have fallen in love with those fastballs before, and they’ve made a whole industry out of separating the high rising fastball and the low diving breaking ball. I can’t say as a matter of fact that this is how Poche is successful, but it’s the best I’ve got for now. Besides, the explanation is less relevant than the reality. What’s real is that Poche has dominated higher-level opponents. That’s the best indicator of success against the highest level of opponents there is.

I don’t know if Poche will get that chance in 2018. Even if he does, it’s unlikely to mean much with regard to the playoff hunt, since the Rays are looking way up at the competition. And of course, there’s no guarantee at all that what Poche is doing can carry over into the majors. No hitters are more skilled than the hitters in the bigs, and they’ve seen so-called deceptive deliveries before. Maybe they’ll sniff Poche out, I don’t know. There’s a reason why players become more valuable when they start to have success in the bigs. It’s because, to major-league organizations, success in the bigs is really the only success that matters.

Colin Poche, then, remains something of an unknown. He’s not thought of as a top prospect, and since he pitches with the Rays, it’s not even obvious what his role should be called. He’s a reliever, but he’s more than that; he’s a starter, but he’s less than that. He’s a pitcher, I suppose — maybe that’s as precise as we need. And I think there are few more intriguing pitchers on the continent. You can’t fluke your way into Colin Poche’s statistics. They’re his statistics that just boggle the mind.