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AT THE 2018 midseason break, Christian Yelich was a 26-year-old first-time All-Star with numbers very similar to those he had been putting up every year of his six-year career: a .292 batting average, 11 homers, 43 RBIs, .823 OPS. In the first game of the second half, he had three hits, and since that day, he has been the best hitter in the world, with an OPS that is almost a perfect match for Babe Ruth's career and a home run rate that's considerably better. From that pretty good first half he went on to win the MVP award. From the one All-Star break to the next, he led all of baseball in average (by nine points), homers (by 13!) and RBIs (by 27!!), a hidden triple crown. He is now more likely than not to make the Hall of Fame.

This is the era of the swing-change superstar: A mediocre player woodsheds his swing with an unconventional hitting guru, tearing down and rebuilding his mechanics piece by piece until he's reborn as an out-of-nowhere power-hitting stud. That's not Yelich's story. Yelich can tell you what he changed at the All-Star break, but he still struggles with the question of why he changed it, and he certainly didn't know anything like this was going to happen. For him, hitting was, and is, a matter of timing, of slowing the game down, baseball's favorite mantra. But in retrospect, his breakout is still mysterious, because so much of hitting -- especially during the most crucial microseconds -- is insanity.

"Over your career, you learn a lot about what it's like to play professional baseball," Yelich says. "You start to understand and listen to your body more. You learn to manage a lot." Joe Pugliese for ESPN

In 1927, while barnstorming through Northern California, Babe Ruth sat with a San Francisco newspaper writer to talk about hitting. "I couldn't explain the secret of it to you if I wanted to," Ruth said. "A lot of times, I never see the ball. That's right. Look at me funny, but I tell you-lots of times when I sense the ball is coming in a certain place, I just close my eyes and swing."

Most baseball takes place in bursts of 400 milliseconds, from when the pitcher releases the ball until it reaches the front of the plate. We perceive the world about 80 milliseconds behind reality (roughly how long it takes a visual signal to travel to our frontal lobe), so for the batter, the 400 milliseconds get cut down to closer to 300. The final 150 milliseconds, furthermore, are too late to be useful: A Japanese study in 2016 had hitters wear special glasses that would go dark at different points of the pitch. The hitters whose glasses obscured their vision 150 milliseconds before the pitch reached the plate were no worse than batters whose vision wasn't obscured at all. (And as the ball approaches the plate, it travels about six times faster than eye muscles can track and leaves the hitter's field of vision entirely.) So the hitter has perhaps 150 milliseconds to recognize the pitch, determine its speed and spin, forecast where and when it will arrive at the plate, and direct his body through a complicated three-part physical sequence that will, in theory, connect a small sweet spot of a 3-foot rod with a ball that the batter can't actually see. It takes normal people, in lab conditions, about 700 to 800 milliseconds to identify a pitch.

If you think about this task, it becomes impossible. Literally. In 2012, researchers at Columbia University measured electrical activity in hitters' brains as they tried to identify pitches. The research concluded, according to an article in Frontiers in Neuroscience titled "You Can't Think and Hit at the Same Time," that the batters who made the wrong decisions showed more activity in their frontal cortex. That's the part of the brain at work when you consciously deliberate on something -- coffee or tea, Hawaii or Las Vegas. Batters who made the right decision showed more activity in the fusiform gyrus, an area in the temporal lobe that plays an important role in object and facial recognition.

"They are athletic geniuses in every sense of the word. This is cognition at its peak," says Jason Sherwin, one of the Columbia researchers and now CEO of deCervo, a startup that developed a training application called uHIT to help hitters recognize pitches more quickly. But of the decision to swing or not swing, he says, "I think it's a non-deliberative choice. As you try harder, you're screwing up the process."

In the moments when baseball is happening, hitters become, essentially, spectators. It would be a stretch to call the decision to swing free will, because it isn't free will when you recognize a face you know on a movie screen. You can't will it; it just happens.

And so, to get back to Christian Yelich, this is the dilemma: The game moves too fast, but trying consciously to slow it down is counterproductive. To beat those 400 milliseconds means mastering every part of the process leading up to it and then taking a leap of faith.

"In baseball, you use your legs a lot more than people realize," he says. "I don't think they realize how much torque and strain you put on those on a daily basis." Joe Pugliese for ESPN

ON THE OFF-DAY before the second half began last year, in the Brewers' clubhouse at Miller Park, Yelich sat at his locker with a tablet and watched old video of himself crushing balls. He wanted to remember what crushing a baseball felt like.

The clips Yelich watched were from summer 2016, when he was still a Miami Marlin, and the memories he was drawing back on were from July 3 of that year. He and the Marlins were in Fayetteville, North Carolina, to play a Sunday night game against the Braves at the Fort Bragg military base. After visiting a parachute packing facility and touring the Army post earlier in the day, Yelich corralled the Marlins' hitting instructors, Barry Bonds and Frank Menechino, for soft-toss drills. It was 91 degrees in Fayetteville, and they were in a makeshift tent that wasn't air-conditioned.

Cage sessions between Yelich and his coaches were often tense, even without North Carolina heat. Menechino's soft tosses came fast, to replicate the decision speeds of game pitches. He designed drills to be competitive, and he talked trash to add to the pressure. Sessions would sometimes end abruptly. Menechino and Bonds always wanted to go step-by-step, reinforcing the small successes along the way; Yelich wanted to see the whole picture all at once. They wanted to work on mindset; he wanted to work on mechanics. They also thought he was a better hitter than he did and wanted him to do things he didn't think he was strong enough to do.

Yelich had been in the Marlins organization for six years. Raised in Westlake Village, California, half an hour north of Malibu, he hadn't come from an intense baseball background. His mom and dad had never played the game, and he had no rooting passion for either LA-area franchise. (He would become a fan of the Yankees, and particularly Derek Jeter.) When he was 7, he tried to quit baseball because he didn't like getting hit by pitches, but his mom bribed him to stick with it.

His swing -- a level left-handed stroke that drew comparisons to that of Mark Grace, one of the great opposite-field hitters of the 1980s and '90s-came naturally to him. A sense of belonging at higher levels often didn't. He worried about being demoted back to the minors long after that was a realistic threat. Yelich -- more friendly than charismatic -- is often described as humble, and he comes by that humility genuinely. It sometimes manifests as risk aversion. He has a tendency to reflexively reject unsolicited observations and advice.

His Marlins coaches knew he had more power than his home run totals showed; they could see it in batting practice and in how hard he hit grounders. Yelich sort of knew it too, but change was risky. (And, to be fair, nobody thought he had Babe Ruth kind of power.) "He was scared to death," Menechino says. "We said, 'Trust us. Keep on the path. You'll never get it right away.' He didn't understand how good a hitter he was going to be. We all knew."

On this day in July 2016, Yelich's coaches were hammering him about the need to "swing down," timeworn hitting advice that was increasingly mocked by progressive hitting coaches as unsuitable to the modern game. The "launch angle" movement was taking hold around the league. A number of prominent veterans had rebuilt their swings to elevate more balls and take advantage of MLB's suddenly lively baseball. In this era, Yelich stood out: He hit the ball hard but mostly on the ground and frequently to the opposite field, wasting his natural power. This wasn't by design. It was just how he hit -- partly his swing, partly his timing. He tended to hit pitches "deep" -- over the plate instead of out in front. He could pull inside pitches, but if the pitch was middle or middle-away, he would carve it to the opposite field. Yelich was regularly asked why he couldn't just hit more fly balls and take advantage of his power. He was sick of that question. Hitting a baseball is hard enough, he said, and trying to hit "up" could backfire spectacularly. "If you're not strong enough," he said in 2016, "launch angle is not your friend."

Still, swinging down? Weird advice for one of the world's most dependable ground ball hitters. But the drill wasn't about his actual swing plane. It was about his mindset. "Everybody has an upswing," Menechino says. "Nobody actually swings down. It's just perception. That drill was about shortening up his path, getting that elbow close to the body, not going around the ball, getting short to it."

So Yelich swung "down" at these hard soft tosses, and things started clicking. He attacked balls on the outer half and got to them out in front of the plate, where he could elevate them. He was arguing with his coaches -- "Swing down? I'm hitting backspin fly balls!" -- but they just kept repeating it: Keep doing it, keep doing it. "You find this mindset, and it's coming off the bat like it really hadn't for me before," Yelich says. "Your body doesn't actually do what your mind thinks, but it's a way to get there."

That summer he had the first real power spike of his life, and he came to realize he'd been late on pitches his entire career. Not so late that he couldn't be successful -- he was good enough at every other baseball skill that he could be a borderline All-Star as a ground ball hitter -- but too late to get to a contact point where he could hit for power. "Timing is a very hard thing to teach," Menechino says. "You can show him how to get ready to hit, but to teach that timing? It's almost impossible." It can only be found, and Yelich briefly -- but fleetingly -- found it.

Then he lost it. He had another solid but unremarkable 2017 campaign and was traded to Milwaukee -- by his childhood hero, Derek Jeter, he likes to point out -- as part of a Marlins fire sale. In 2018, he found himself in a pennant race for the first time.

So that's what he was thinking about when he watched the video the day before the second half in 2018: How can I regain that feeling? How can I get my timing right, to where I'm hitting the ball in front of the plate instead of deep into my swing?

He went to the cages at Miller Park. On something of a whim, he tried standing more upright, his feet closer together, hands a little higher, shoulders squared. This was how he'd swung in high school, so it wasn't a foreign swing. When he entered professional ball, he had changed his swing to be more spread out, lower, in part because it made it easier for him to recognize the much faster pitches that he was seeing for the first time. Now, though, he'd been a major leaguer for six years. He'd seen thousands and thousands of such pitches. He was better at thinking through the sequences that pitchers were likely to use against him. And he was calmer at the plate -- there wasn't so much blood rushing to his head anymore.

So he stood more upright. With that, he found that his load -- the precommitment stage when the batter draws back and collects energy -- put him in a position to pause, for a fraction of a second, before attacking the ball. He was slightly earlier, balanced and ready to stride toward the ball. Balls weren't getting deep; he was hitting them out in front. This changed the trajectory of his batted balls.

Perhaps more important, though, this new load allowed him to feel -- mentally, subconsciously, in the milliseconds when his fusiform gyrus was doing the pattern-recognition work to determine whether he could hit a pitch -- that more pitches seemed hittable. Here is perhaps the most telling thing that happened after the 2018 break: He started swinging at far more pitches early in counts. In the first game of the second half, he had three one-pitch at-bats (lineout, double, triple), as many as he'd had in the entire month of April. He had as many first-pitch hits in that first three-game series as he'd had in the two months before the All-Star break. He went from one of the more passive first-pitch swingers in baseball in the first half to one of the most aggressive. This was, he swears, an entirely unintentional change; it was just the result of being in a position to pull the trigger. He never chose that as a strategy. This was not his frontal cortex. His brain was choosing it for him.

He admits this all may sound like "insanity," but he abides by one rule of hitting: "It doesn't matter how good your swing is or what pitch you swing at. If you're not on time, you can't hit it." As he kept tinkering in the next few weeks, he found more and more confidence attacking pitches in all parts of the strike zone. He especially swung more frequently at pitches away, which is where he gets pitched most frequently and which is where he had most often (but no longer) sliced hard ground balls. He was now hitting those pitches better than he ever had, turning the pitchers' plan of attack into his strength. He pulled more balls, hit more balls in the air, pulled more balls in the air. He denies trying to do any of that, exactly. "He's on autopilot," Menechino says approvingly. "He doesn't have to feel for it."

Some players have rebuilt their swings piece by piece, deliberately, but for Yelich it required the opposite. When he stared directly at the problem -- too many ground balls, not enough fly balls -- he doubted himself. "I accidentally stumbled upon something that really helped me," he says. The hitting coach texted his former pupil a few weeks into the second half: "Are you starting to believe you're a Guy now?" "I don't even understand what's happening right now," Yelich replied. "But I believe it."

"You play baseball every single day, so whenever something does happen, like you run into a wall or you get banged up, it doesn't really have a chance to recover," Yelich says. "You're just kind of riding out with that for the rest of the year." Joe Pugliese for ESPN

THERE IS A fairly common feeling humans get called High Places Phenomenon. It's the rush of anxiety you might have at the top of a high building, or driving along a mountain pass, that despite your conscious longing to stay alive you will suddenly jump over or veer off. It's a fear that the parts of your brain that you don't believe you control will start driving you.

This must be what it's like to be a wildly successful hitter yet to suddenly feel the despair that your brain -- the part of it you can't control -- is going to rebel and fail you. Hitting is an act of faith, and faith in any context is constantly challenged, always wavering.

When Yelich is standing in the on-deck circle or walking to the plate, he sometimes gets a feeling, a you've got absolutely no chance right now kind of self-doubt. "It just leaves you," he says, "it" being the feeling of control over the most consequential moments of his life. "I don't know why. The first time it happens to you, it scares the s--- out of you." Sometimes that lasts one at-bat. Sometimes it lasts for weeks. "And then, eventually, it sounds stupid, but it's one swing -- whether that's in BP, or the on-deck circle, a groundout in a game, a hit, and you're just like, 'Oh, there it is.' It comes and goes, just like that. That's why it's so maddening. It drives people in baseball insane."

In the end, there is only so much a hitter can rely on with eyesight. And only so much he can control outside that: He can refine his swing until it's automatic. He can study his own failures to understand how pitchers are going to attack him. He can prepare for each individual matchup so he can anticipate what pitch will be thrown, and he can learn to process sequences in the 15 seconds between each pitch so he can send simple pre-pitch cues to his subconscious. He can learn how to distract himself when he's in the on-deck circle and blood starts to rush to his head. He can slow everything down, but then the pitch comes, a pitch he sees for 150 milliseconds, and the hitter can only turn within himself, to a faith that what he has done before he can do again.

Sometimes, Yelich gets the opposite of the "there's no way I can ... " feeling: The game seems like it's in slow motion. But that feeling passes too, and eventually he has to deal with the bad one again-even now, after more than a year as the best hitter in the world. "I know this," Babe Ruth concluded in that 1927 interview: "A man can't worry and hit home runs."

Yelich has been through it before, dozens of times. Now he can slow the game down. He can take a deep breath. He can distract himself with the plan he settled on before the game for attacking this pitcher and remind himself that the feeling is not real. He can avoid the paradox that drives so many players insane -- the one where trying harder makes you worse. He can tell himself, somewhat unconvincingly but nonetheless helpfully, that it will pass. And so far it has.