The Tampa Bay Rays are not sneaking up on anyone. Not anymore. Between a 13-game winning streak to start the season, their stature atop baseball’s best division and 22-year-old Wander Franco’s affirmation that he’s a superstar-in-the-making and an MVP candidate right now, the Rays have shed their nerdy Clark Kent glasses — or at least added a cape.

Out in front, leading with a cartoon hero’s thundering steps and well-defined pectoral muscles, is Yandy Díaz. The 31-year-old Cuban infielder bats leadoff every night in Kevin Cash’s lineup, and right now, he’s the best hitter on the team. By OPS+, the park-adjusted measure of offensive production, Díaz ranks fifth in MLB.

The difference between the solid contributor Díaz has been for years and his keeping company with the likes of Aaron Judge and Yordan Alvarez this season has come in the power department. Long a master of getting on base, Díaz is now also running a career-best .539 slugging percentage. Having crushed 12 homers already in 2023, he will almost certainly eclipse his personal best (14 homers in 2019) before the All-Star break.

The long wish-casted development — for the man whose appearance inspires muscle emojis to add them to his stat line — is a product not of Díaz changing who he is as a hitter but of gaining the security to take some chances.

Getting on base to secure a future

The first impression of Díaz often swings more toward “Holy biceps, Batman” than an appreciation for his superlative baseball skills. Back when Díaz originally surfaced in Cleveland’s organization, the internet’s favorite photo of him wasn’t on the field. It was in the gym.

He was, in essence, baseball’s DK Metcalf. But that sort of visible physical potential, which is far from a direct line to success in football, tells you even less about a player’s future in baseball. (For the record, though, Díaz said he successfully bench-pressed one rep at 400 pounds this offseason.)

As Díaz broke into the majors, he provided an almost flippant commentary on the sport. In the first 88 games of his career, split across 2017 and '18, he managed one home run, while his unimposing, 5-foot-9 teammate José Ramirez bashed 68 by learning to lift and pull the ball like clockwork.

After Díaz landed with the Rays in a three-team trade ahead of 2019, Tampa Bay hitting coach Chad Mottola was initially curious whether Díaz's shredded upper body afforded him the flexibility to get to all the pitches he needed to hit. The answer to that was yes, but Mottola found that Díaz took the most pride in maintaining his razor-sharp eye at the plate.

Since joining the Rays, Díaz has the 10th-lowest chase rate in baseball, swinging at only 19% of balls outside the strike zone. Between 2019 and 2022, he hit only 38 homers but walked nearly as much as he struck out and logged a .374 on-base percentage that ranked among the top 15 in baseball over that span. That level of plate discipline — which puts Díaz in the realm of Juan Soto, Mike Trout and Brandon Nimmo — combined with his ability to put the bat on the ball gave Díaz a rock-solid baseline that was in many ways more precious than home run power in today’s MLB. As long as he maintained that, he would be a big-leaguer.

“I think I’ve always been a contact hitter rather than a power hitter,” Díaz told Yahoo Sports in Spanish through Rays communications manager Elvis Martinez, “even though the power is there.”

The drumbeat of calls for him to add power quieted as Díaz established himself as a productive player, but they never went away. Invigorated by Statcast metrics that showed he did indeed post top-of-the-charts maximum exit velocities, fans, analysts and teammates wondered what it would look like if Díaz adjusted his launch angles, if he bought into the mantra of “elevate and celebrate.”

“Because of the strength I have physically, naturally, they didn’t make fun of me,” Díaz said, “but they were like, ‘Swing, swing, swing so the ball will go [out] ‘cause you’re so strong.’”

This offseason, Díaz reached a deal with the Rays on a three-year, $24 million guaranteed contract that took him off the year-to-year arbitration schedule. It bought out one would-be free-agent season and gives the Rays a club option for 2026. And with the future more secure, Mottola found that Díaz was open to trying more things outside his comfort zone.

“Being comfortable with what he was good at and just staying within that box is something where he knew he was going to make a lot of money,” Mottola said. “Now that the contract came, it was, ‘OK, let’s explore where your ceiling is. Let’s make some mistakes and see if we can get more power.’”

How Díaz is tapping into his strength

The way Díaz tells it, his uptick in home run power is about pitch selection — a remarkable claim for someone who was already one of baseball’s choosiest hitters. But it’s not just about swinging at strikes and laying off balls. It’s also about recognizing the moments when the game allows for a bolder move.

For a hitter, that’s when he has forced the pitcher into throwing a strike.

“We’re just trying to encourage him to take more shots in advantage counts,” Mottola said, adding that the opportunistic approach has been a focus across the team.

That’s why, if you go looking for visual evidence of Díaz's changes, you probably won’t find much. For all the mid-2010s chatter about swing changes, the best way to achieve power has proven to be more about bat speed and timing. Connecting with the ball earlier in its flight, in front of the plate instead of over top of it, leads to more fly ball contact and more home runs.

But as Eno Sarris recently explained in detail at The Athletic, that inherently means starting to swing earlier, which cuts down on the already microscopic amount of time hitters have to determine whether the incoming pitch is a good one.

That means Díaz, who builds his game off his expertise in that arena, has to push himself to get just a touch reckless, in a calculated way, in game situations in which he is likely to get a pitch he can drive.

“It’s actually led to some decisions he hasn’t liked and to expanding the zone at times, probably a total of 10 times on the season,” Mottola said. “But we keep giving him the message that those are worth what you’re doing.”

So when Díaz talks about pitch selection, it’s about selecting when to start his forward motion a bit sooner, when to throw a little caution to the wind, when to unleash the power stored in his impressive frame.

“I don’t like to hit a lot of pop-ups,” Díaz said, maintaining a focus on the bad outcomes he works so hard to avoid, “so when I hit a homer, it just comes from selecting better pitches and swinging harder.”

Hannah Keyser contributed reporting to this story.