Samuel Basallo says one plate appearance led to his Orioles breakout. Here’s how.

BOSTON — Samuel Basallo can trace this turnaround back to the exact plate appearance when it all began going his way.

He was in Kansas City against the Royals, facing right-hander Seth Lugo in the second inning on April 20. Basallo laid off three balls, Lugo worked the count full and then Basallo watched a low sinker, taking his free 90 feet.

What changed in that moment is hard to describe. “I think it was a feeling, for sure,” Basallo said through team interpreter Brandon Quinones. There is no way to measure the confidence a single moment can bring, or how one decision — taking a pitch, earning a walk — can create a cascading effect.

But Basallo is sure of one thing. That one plate appearance was the beginning of what has been a momentous stretch for the 21-year-old rookie.

“The way I was standing, I was feeling really uncomfortable up until that point,” he said. “Feeling almost a little lost at the plate. From that point on, I remember feeling just a lot more comfortable and being able to settle into my stance and going from there.”

The irony is that it took not swinging to unlock a swing that has been devastating. Part of his success has come from aggressiveness, swinging early and often, even if that means he’s attacking pitches outside the strike zone. That has long been a blemish on Basallo’s game, but chase rate is forgivable when paired with the heavy damage he has doled out lately.

Entering Tuesday, Basallo hit .363 with a 1.044 on-base-plus-slugging percentage since April 20, the game in which he walked against Lugo in his first plate appearance. The rest of that game, even at that time, seemed to foretell a breakout. He finished 2-for-3 with two walks, and those two knocks came as opposite-field RBI singles, including one that kicked off a 12th-inning rally that sealed the game.

Looking back now, those two singles to left field stand out to manager Craig Albernaz. They were the “the first time where I’ve seen it from him where he literally just took the nice, easy swing and hit the line drive the other way,” he said.

There is no question that Basallo is a power threat to all fields. But as right-handers hammer him with backdoor cutters or low-and-away changeups, and as left-handers sweep their arsenal away from Basallo, his ability to stick the bat head out for a hit unlocks another level.

“When he started doing that,” Albernaz said, “that’s when the season really kind of took off for him.”

It’s only the beginning of June, so there is ample time for Basallo’s results to turn. When a player doesn’t walk much — his May walk rate was 7.1% — they are susceptible to slumps. But at this point, Basallo appears to be a strong candidate for the American League Rookie of the Year award.

His Statcast page looks impressively similar to the one Gunnar Henderson produced during his AL Rookie of the Year campaign in 2023. Henderson walked more and chased less than Basallo does, but some of the biggest indicators of young success — Henderson was also 21 for the first part of that season — match up.

Hard-hit rate: Henderson at 52%, Basallo at 48.3%. Bat speed: Henderson at 75.5 mph, Basallo at 75 mph. Average exit velocity: Henderson at 92 mph, Basallo at 92.7 mph.

Those are indicators that this isn’t a fluke. Basallo is among the best in baseball when it comes to putting the ball in play — and doing it at a high velocity.

“I hate striking out,” said Basallo, who still strikes out in about a quarter of his plate appearances. “Thank God, ever since I was a kid I’ve had the ability to put the bat on the ball. Obviously, I have the strength to go with that and the ability to, even if I don’t pull the ball, be able to go the other way and hit the ball hard. I really want to put the ball in play, and I really believe that when you do put the ball in play, good things can happen.”

When April turned to May, several underlying changes occurred. For one, he’s swinging more and missing less. His whiff rate in May was 27.3%, down from 34.5% in March and April. His hard-hit rate rose slightly to 50% that month. And while he’s striking out a bit less, Basallo is also walking less — it aligns with his focus on putting the ball in play.

The most notable change between months, however, is how Basallo stands in the box. When he walked against Lugo, Basallo said he felt something different — almost more mental than anything else, a swell of confidence that turned into a superb May.

But in March and until April 20, on average, Basallo stood 29 degrees open (meaning his hips and front foot faced right field) with 21.6 inches between his feet. He was deep in the box and 25.3 inches off the plate, according to Statcast’s measurements.

In May, Basallo closed his stance slightly to an average of 22 degrees. He widened his stance, with 28.2 inches between his feet. He moved up slightly in the box and moved a little closer to the plate. They were small tweaks, but when melded with confidence, they led to big results.

When Basallo arrived in the majors last year as the top prospect, he went through the typical adjustment period for most hitters. There were bright spots, but he finished his first taste of the big leagues with a .165 average and .559 OPS.

There will be more downturns in Basallo’s career. But what May showed is how highly he can soar.

“I was able to learn a lot from last season. I was able to learn from the failures and the frustrating moments,” he said. “Really take a lot of those things and put it into practice and try to improve a lot of those things. And, thank God, I’ve been able to have a lot of success so far this year.”