Although the Yankees ultimately put the A’s away by a somewhat lopsided margin, it was right in the middle that the A’s had some life. Luis Severino was surprisingly allowed to start the top of the fifth, and with the score then just 2-0, he gave up consecutive singles. Matt Chapman was due up. He’d be followed by Jed Lowrie. He’d be followed by Khris Davis. Aaron Boone went to his bullpen, with the game threatening to swing in the other direction. The pitcher he went to was Dellin Betances.

Within a few minutes, the inning was over, and the score was preserved. Betances went 1-2-3 again in the sixth, and then the Yankees pulled away. According to Win Probability Added, Betances wound up making the biggest positive contribution on the Yankees’ roster. Such territory was hardly uncharted; Betances was one of the best relievers in baseball for years. But in 2017, he lost the ballclub’s trust. Joe Girardi didn’t even use him in the wild-card game, and subsequent appearances were mostly low-leverage. A year ago, Betances had nobody’s faith. Wednesday, he was first out of the pen.

The playoffs have only just started. Yankees fans became reacquainted with the good Betances months ago. So this is nothing especially new. I’ll also say that Betances wound up buried last October in part because the rest of the bullpen was already so deep. The Yankees could afford to stay away from Betances, because they had so many other weapons. Really, he wasn’t *that* bad. He was as hard to hit as ever. He just had his problems with strikes. Made him feel too risky with the stakes as high as they get.

Yet, by and large, those problems have gone away. Betances has long had his bouts with wavering control, and people have frequently blamed his height. He’s no shorter now than he ever was, but nearly every important indicator has improved since last season. I looked at every single pitcher who threw at least 50 innings in each of the last two years. Here are the ten pitchers with the biggest improvements in strike rate.

Betances has moved, from bad to above-average. This has basically been mirrored by an increase in swing rate — the rate of swings against Betances went up eight percentage points. Betances has been throwing more competitive pitches. When you’re throwing more competitive pitches, you’re more around the zone, and you’re more likely to compel a swing. A year ago, batters were more than happy to just wait Betances out. Now he’s not letting them get away with that approach. This next table shows a major reason why. You’re now seeing the biggest improvements in first-pitch-strike rate.

No one has ever wanted to face Dellin Betances. But when you’re facing Dellin Betances, you’d much rather be ahead than behind. A year ago, Betances struggled to throw even half of his first pitches for strikes. That rate has recovered, putting hitters more on the defensive. You can be more patient with zero strikes than you can be with one strike. This all ends up being reflected in the walks. Here are the biggest improvements in walk rate.

And, relatedly, here are the biggest improvements in strikeout-minus-walk rate.

Betances hasn’t eliminated walks altogether. He doesn’t have pinpoint command, and he gets himself into so many deep counts. He gets into a lot of those deep counts because he routinely posts one of baseball’s lowest contact rates. Even last season, hitters found Betances very tough to square up. So instead of swinging, opponents just waited him out. That’s no longer so much of an option. Betances has been pitching like he’s back at his peak.

As part of an effort to try to explain what’s happened, take a look at Betances throwing a fastball last October:

Here he is throwing a breaking ball:

And now here’s a fastball from Wednesday:

And here’s a breaking ball:

I don’t mean to suggest that everything comes down to mechanics. For all I know, Betances might be in better physical shape. Maybe these days he’s better prepared. Maybe these days he’s more psychologically focused. There could be any number of factors contributing to Betances’ recovery, but just looking at those videos, two things stand out to me. One:

Betances no longer uses such a high leg kick. Related to that, he no longer turns his upper body away from the hitter so much. You can think of it as a simplification, as Betances gets to a more conventional balance point at the top of his delivery. And then, later on, two:

This could be related to what we just looked at, or it could be separate. But, you’ve heard of pitchers throwing across their bodies? Betances would do the opposite of that. He’d open up, and he’d open up early. As you compare these images, look at Betances’ left foot. In the shot from 2017, it plants over on the first-base side of the rubber. In the shot from 2018, it plants more straight forward. This is one of those pitching fundamentals — you’re generally taught in high school to stay in line with the plate. Betances was no stranger to flying open, and it’s something he did for a while, but he might’ve lost his ability to compensate for that. He’s put a hell of a burden on his body over the years. People get older. People need to adjust. Betances is now throwing with less force pulling him off to the side. His upper body and lower body seem like they’re more in sync, and even though that’s just speculation based on some TV feeds, the numbers back it up. The numbers back something up. The pitcher on the right looks like a pitcher who’d throw more strikes. He wouldn’t pull so many pitches, or leave so many pitches up to the arm side. The pitcher on the right has indeed been more successful. The stuff has never once been a problem. It’s always been location.

As the Yankees played and then were eliminated in 2017, it felt like Betances would have to move on. Or it felt like the Yankees would have to move on from Betances. He felt to me like one of the most obvious trade candidates in baseball, because he’d lost his manager’s trust. Instead, it was the manager who went away, and Betances was given a new opportunity, the club showing faith in his talent. Suffice to say that Dellin Betances is back. His low was never too terribly low, but his highs are as high as high gets.