SAN DIEGO -- Kirby Yates got his introduction to the Padres' closer tradition in the best way possible.

In the summer of 2006, Yates flew to San Diego to watch his brother, Tyler, pitch for Atlanta. With the Padres clinging to a late lead, the bullpen doors opened, "Hells Bells" clanged, and Trevor Hoffman shut down the Braves.

"I remember getting goosebumps," Yates recalled.

Now Yates is the one opening those doors. Since his arrival in San Diego two years ago, he's become the most dominant reliever no one's talking about. Take a look at the relief ERA leader boards since the start of last season:

1. Blake Treinen, 0.78
2. Jeremy Jeffress, 1.26
3. Sean Doolittle, 1.47
4. Edwin Diaz, 1.89
5. Kirby Yates, 1.92

Relief ERA isn't always a great barometer but the rest of Yates' numbers also stack up. In that time, he's ranked fifth in strikeout rate minus walk rate (30 percent), eighth in xWOBA: (.198), ninth in FIP (2.28) and strikeout rate (37 percent).

This year, Yates is the only pitcher in baseball with a strikeout rate higher than 40 percent and a hard-hit rate lower than 20 percent. The Padres have needed every ounce of those efforts. They've won 12 games, all by three runs or fewer, and Yates has finished 11 of them. He's atop the NL with 10 saves, and he owns a 0.75 ERA with 19 Ks in 12 innings.

Yates has followed a long line of excellent Padres closers, and he's lived up to the standards set by Hoffman, Goose Gossage and Rollie Fingers, among others. Nationally, he’s not quite so well-known. Yet.

Who is Kirby Yates?

Aside from one of the most dominant relievers in baseball, he's an unassuming, laid-back Hawaiian. Yates is 5-foot-10, rocks a mohawk and serves as the bullpen’s funny guy. He just turned 32, after a winding career in which it took a decade to develop his splitter into one of the sport's nastiest pitches.

"He's not the body type you'd expect in a closer," said Padres skipper Andy Green. "He's not the package you'd expect in a closer. But he's every bit a closer."

Yates went undrafted out of college in 2008 and '09 after missing two seasons because of Tommy John surgery (he had been taken in the 26th round out of high school by the Red Sox in '05 but didn't sign). That gave him the appropriate chip on his shoulder.

"In the Minors, if I was pitching, and I was facing a first-rounder or a second-rounder, I knew it," Yates said. "I was totally conscious of that. I wanted to make a point, I wanted to strike them out. I want to test myself. But it got to a point in Double-A or Triple-A where I was just like, I don't care who you are anymore. I'm good enough."

How did Yates get to San Diego?

Yates spent two seasons in Tampa Bay and a season with the Yankees. He pitched middle-relief with middling results from 2014-16. Following the '16 season, Yates recommitted himself. He moved to Arizona, where he could intensify his offseason workouts. He began throwing his splitter. Yates felt he was poised for a big season.

Then, in an early-season bullpen crunch, Yates was cut by the Angels after just one appearance.

"Out of all the teams, out of all the times, that was the only time where I thought, 'OK, you guys messed up,'" Yates said. "I got why Tampa got rid of me. I got why New York got rid of me. I understood. But that one, I didn't."

The Padres were happy to swoop in. Their scouts liked Yates' splitter, even if he'd only been throwing it for a couple months. At first, Yates was stubborn in ditching his slider. But his results with the splitter didn't lie.

"Every time I threw a good one, I got a swing and miss,” Yates said. “I didn’t know how to use it at first. But that told me, 'Wow, this is going to work.' I just need to get it consistent."

Why is he so good?

Easy. Nobody hits Yates' splitter. Since he began using the pitch, opponents are batting .127, slugging .182, and they have a .168 xWOBA against it.

The reason it's so effective: It's the perfect complement to his fastball -- a pitch with nearly 1,000 more RPMs. Yates is basically 60-percent fastball, 40-percent split, and that mix has baffled opposing hitters.

"They come out exactly the same and go two different directions," said Craig Stammen, Yates' catch partner. "Honestly, if I could pick any two pitches that match up perfectly, I'd pick those two."

Yates isn't one to get rattled either, given his winding career path. He spent most of last season with a severely sprained ankle and pitched anyway, assuming the closer role in mid-July, when Brad Hand was traded to Cleveland.

"Last year he played with a dang near cast on his ankle all year," said bullpen coach Doug Bochtler. "You see that blue-collar workingman's mentality with these amazing results. You see that, you know what he's been through, and now he's one of the top closers in the league."

Time for the baseball world to take notice.