The people are growing accustomed to watching the Mets win, and as a side effect of that, the people are growing accustomed to watching Jeurys Familia come in to try to finish the job. Familia has yet to allow a postseason run, and even if you didn’t know anything about him before, you’d be able to tell just from observation that he’s far from a weakness. They say the biggest vulnerability on the Mets is the soft underbelly of the bullpen, and though that would be true for most teams, the Mets make it extra tricky, because the starters often work deep, meaning they can hand the ball to Familia almost directly. Which means there’s almost never any let-up.

What Familia has turned himself into is one of the true reliever elites. It hasn’t always been a smooth and easy path to the top, as Familia has previously fought his own command and struggled to retire left-handed hitters. Both of those are common problems for hard-throwing righty relievers, but Familia this year has overcome them, blossoming into a shutdown closer Terry Collins will trust to get more than three outs. And the thing about Familia is that it goes beyond just his being successful — these days, he arrives at his success on a path all his own.

Let’s start with something of a throwaway point. Kind of a curiosity. So, Familia throws hard. Big, moving sinker, and everything. Here’s a sinker he threw in Game 2 to Starlin Castro:

Just from eyeballing it, you don’t even want to call it a good pitch. It seems like a pitch that was way too low. Generally, you want your fastballs to be somewhere close to the hitting zone. But ultimately, Castro did swing, and of course he missed. You can’t just ignore that. So let’s move ahead. PITCHf/x has a “swinging strike” designation, but along with that, it also has a “swinging strike (blocked)” designation, for whiffs on pitches in the dirt. You’ll see those often with curves and splitters. You don’t get that often with fastballs. When Familia got Castro to whiff, it was the fourth time this year Familia got a swinging strike on a fastball that got blocked. Four times isn’t much of anything, as baseball goes, but only Zach Britton did this particular thing more. Granted, he did it a lot more (13 times), but still. Britton has a lethal sinker he leans on almost exclusively. Familia’s sinker has something of a Britton-ish quality.

But this isn’t really about the sinker. This is about a different pitch, a newer pitch, a pitch that’s already made waves in New York. So this won’t be new to many of you, but, here’s Familia’s last pitch from Sunday:

Here’s an earlier version:

Look closely and you’ll see a “94”. So you assume, because you have to, that’s a .gif of a fastball. It doesn’t make sense that it wouldn’t be, but some things just don’t make sense. Jeurys Familia throws a splitter now. His splitter can touch the mid-90s. That’s every bit as stupid as it sounds.

The origin story is funniest if you just read Jon Heyman’s latest column:

Jeurys Familia just picked up the splitter one day in July, and that was that. Catcher Travis d’Arnaud recalled Familia coming to him one day, and saying, “OK, I throw a splitter now.”

In truth, the splitter had long been a project, and Familia was working on it on the side to try to gain a third pitch. He went through the minors with a below-average changeup, and he eventually wanted to offer a different look. So Familia didn’t just wake up one day with a splitter, but he did debut it all of a sudden, around the middle of August, and since then a reliever who was already good has looked nothing shy of spectacular. Through August 10, Familia threw about 74% fastballs and about 25% sliders. Since August 12, Familia has thrown 64% fastballs, 15% sliders, and 21% splitters. Put more simply, Familia has almost totally replaced sliders to lefties with splitters, and he hasn’t looked back. Since the pitch first showed up, Familia has used it with the utmost confidence.

This year, before the splitter, Familia threw nearly two-thirds of his pitches for strikes. Yet over the past two months and change, he’s thrown 71% of his pitches for strikes, which means Familia has become a reliever who’s very commonly ahead. Which makes his pitches only more lethal, as hitters have to expand, and sure enough, since the splitter came around, Familia has earned plenty more swings out of the zone. Everything has gone in the right direction, with very few mistakes.

Without question, this is the real insanity. This is the core of the whole post. I made use of the Baseball Prospectus PITCHf/x leaderboards and looked for secondary pitches thrown at least 50 times. So we’re looking at sliders, curves, changeups, splitters, and knuckleballs. Here are the very fastest of those pitches, sorted by average velocity:

It’s not that Familia’s in the lead. We know he throws hard. It’s that he’s in the lead by damn near three full miles per hour. The gap between everyone else in the table is less than one tick. Familia leads Arrieta by 2.9, and Arrieta’s pitch might be considered a cutter, and then cutters are a sort of fastball. When you dig deeper you start to realize there aren’t actually clean boundaries between pitch types, so maybe it doesn’t make perfect sense to split secondary pitches and primary ones, but we see that Familia throws what he calls a splitter faster than the majority of pitchers throw fastballs. The pitch looks like a splitter to opponents, too, so I’m not making anything up. This is an absurdity, but it’s an absurdity that Familia has brought to the biggest stage. It’s an absurdity that’s currently one of the reasons the Mets are two wins away from going to the World Series.

The secret for Familia, presumably, is that he doesn’t bury the ball so deep in his hand. Maybe he doesn’t spread his fingers as much as the average pitcher does for a splitter. He might throw more of a split-fingered fastball, while the next guy might throw more of a true splitter, and again, pitch-type classifications aren’t perfect. But we see here one way in which Jeurys Familia appears extraordinary. There’s no one else doing this. I’m not sure there’s anyone else who can do this. Even the Aroldis Chapman changeup hovers around 89.

No one does what Jeurys Familia does. Familia throws a non-fastball in the low- to mid-90s. He commands it, too, just as he commands his other pitches, the ones that made him good before he got even better. In a postseason full of breakout stories, Familia has to have one of the craziest. Or at least one of the most unfair.