ST. PETERSBURG -- Rich Hill famously reinvented himself in 2015, when he went from the Nationals’ farm system to independent ball before finding success in the Majors. He changed where he stood on the pitching rubber, adjusted his arm angle and committed to his two best pitches to start the successful second act of his career.

But one secret to Hill’s success and longevity is that he’s constantly reinventing himself. Even in his 17th Major League season, with his 10th big league team, you’ll see Hill use different arm angles in the same inning, adjust his delivery to disrupt hitters’ timing and constantly experiment from start to start.

“It's very unique. It's more of like an older regime thought process, in terms of just the creativity that he employs. He's very instinctive,” Rays pitching coach Kyle Snyder said. “It's a lot of what kind of separates him from the pack and has probably allowed him to have continued success, just given the open-mindedness that he approaches his craft.”

The 41-year-old left-hander enters his start Tuesday night at Nationals Park with a 3.52 ERA and 78 strikeouts in 76 2/3 innings over 15 starts this season. He was the American League Pitcher of the Month in May, posting a 0.78 ERA over six outings while helping the Rays enjoy their best month in franchise history. He’s earned an All-Star endorsement from manager Kevin Cash.

Hill revived his career by leaning into the data-driven science of pitching, but he remains endlessly fascinated by the art form.

“That's the whole thing. Things that we can quantify are easy to point to and say, 'That is it. That's the answer,’” Hill said. “The things that you can't quantify, like intensity or passion or aggressiveness or how comfortable is that player out there in his own skin? I think that's something else that will create more freedom. And when you create the freedom, then you have the freedom to create.”

Past to present

With two outs in the fourth inning of the Rays’ 8-2 win over the Red Sox last Wednesday, Hill scaled the mound to face Boston’s Bobby Dalbec.

His first pitch was a 72 mph curveball from his standard arm slot. Dalbec swung and missed. Hill’s next delivery looked the same -- hands reached back over his head, right leg kicked in the air -- until he lowered his arm angle a bit to drop in a 71 mph curveball that Dalbec took for a strike. Finally, Hill went to a full sidearm release and let loose a 69 mph breaking ball that made Dalbec whiff again.

In one at-bat, Hill practically turned himself into three different pitchers.

“He's the only guy that I know who could do that,” Rays left-hander Josh Fleming said recently.

You’ll occasionally see Hill abandon his over-the-top delivery and drop his left arm down to more of a sidearm angle to fling fastballs and big-moving curveballs by hitters. He’s been doing that for years. He said he first used that technique as a younger pitcher with the Cubs, looking for ways to combat left-handed power bats in the National League Central like Ken Griffey Jr. and Prince Fielder.

He was an effective pitcher then, posting a 115 ERA+ from 2006-08. Then came the injuries, starting with shoulder surgery while with the Orioles in 2009. He opted out of his contract with St. Louis in 2010 and wound up signing with the Red Sox, close to his home in south Boston. He had Tommy John surgery in 2011 then bounced around as a sidearm reliever with the Red Sox in 2012, the Indians in ’13 and the Angels and Yankees in ’14.

The next part of Hill’s journey is well-known: He opted out of his deal with the Nationals in June 2015, went home to Massachusetts, worked out with an American Legion team and threw baseballs off brick walls when nobody else was available. A Red Sox official recommended that he move to the third-base side of the rubber to improve his command and suggested that he give independent ball a shot.

“I just thought, if I was going to do this, I'm going to come back as a starter,” Hill said. “And if I'm going to go to independent ball, I'm going to go as a starter.”

He quickly returned from his time with the Long Island Ducks as a starter with an over-the-top delivery, parlaying four excellent starts with the Red Sox into a free-agent deal with the A’s, then a lucrative extension with the Dodgers. He’s been flummoxing hitters since then almost entirely with four-seam fastballs and his signature curveball, a strategy he committed to after a meeting with Brian Bannister, a former pitcher who’s held front-office roles with the Red Sox and Giants.

“I had heard from scouts, like way back in 2005 and 2006 when I was coming up, that they didn't think that a curveball and a fastball would just play in the big leagues,” Hill said.

A decade and a half later, he’s still proving them wrong. He signed with the Rays in February, continuing his pursuit of an elusive World Series championship while never ceasing to evolve.

“When you have X amount of years under your belt, you learn different things. You learn how to attack hitters. You learn how to manipulate the baseball in certain ways,” Rays catcher Mike Zunino said. “And it's extremely fun for me calling pitches, just working along with him, because sometimes I don't know where he's going to go with certain stuff.”

Creative freedom

Last Wednesday, Hill’s hardest pitch was a 90.2 mph fastball to J.D. Martinez, the 120th-fastest pitch in that game alone. The game’s 41 slowest pitches were thrown by Hill, including a 66.2 mph, drop-down breaking ball to Alex Verdugo. He allowed one run in five innings.

On June 5, Hill breezed through five scoreless innings against the Rangers at Globe Life Field. Six of his 59 pitches were changeups. That might not seem particularly notable -- except he hadn’t thrown a single changeup in his first 11 starts, 57 innings and 847 pitches of the season.

In a 2-1 loss to the Royals on May 25, Hill sped up and slowed down his delivery throughout the night. He implemented a Clayton Kershaw-esque pause in his delivery before firing a fastball by Salvador Perez. He struck out 13 batters while recording 27 swinging strikes over eight innings.

“That part of pitching, you just don't see it as frequently as maybe you did 15, 20, 30 years ago. It's turned into such a power game and power pitchers -- and rightfully so, those guys are really talented -- but there is an art to doing it,” Cash said after that game. “I say [Hill gets] creative, but there's a lot of athleticism to be able to throw a ball 90 mph, altering your delivery pitch to pitch.”

Hill is more than twice as old as his youngest teammate, 20-year-old Wander Franco, but he’s a fascinating philosophical blend of old school and new. He’s embraced the modern use of high four-seamers and diving curveballs, ditching most other offerings in favor of his two best pitches, based on objective information. But his emphasis on disrupting timing and reading swings is more of a throwback.

As a younger pitcher, Hill said, he worried less about the craft and more about making every pitch perfect. Now, he compares the mental side of pitching to icing a kicker in football -- but with far more options available than just calling a timeout. That’s why you might see him throw his first changeups of the season in June or spend a bullpen session working on slide-step breaking balls.

Hill said a lot of his improvisation is based on feel, understanding what his body can do on a given day and what he can’t do in certain situations. That knowledge comes from experience, he said, and a willingness to take risks with an emphasis on the thought process behind each pitch more so than the result of the plate appearance.

“A lot of what makes Rich good is just this variance that is kind of spawned by his creativity and who he is as a person, so it's been a lot of fun,” Snyder said. “Just the art that he brings to it is really, really cool. I love it. I think it's kind of a missing link in some respects in today's game.”

Hill said he draws inspiration from the pitchers he’s seen and played alongside, taking note of how they throw off hitters’ timing and adding some of those methods to his repertoire. He takes everything into consideration, even seemingly minute details like how he walks around the mound or what he says to a hitter on his way back to the dugout. He’s also a student of history, pointing to the creativity shown by pitching legends like Bob Gibson, Sandy Koufax and Luis Tiant.

“Yes, it is fun. But there's also a purpose behind it,” Hill said. “It's like you're trying to create some kind of little bit of magic out there. And that's what's fun. That's what I enjoy.”

What else does Hill have in mind? Where else might that lead him in the second half of his 17th season?

“I’m still interested in knuckleballs,” Hill said, laughing.