This story was excerpted from Adam Berry’s Rays Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

MIAMI -- It didn’t take long for the Rays to help Robert Stephenson make his best pitch even better.

The 30-year-old reliever had always wanted to throw his bread-and-butter slider harder, but he could never figure out how to make it work. That changed shortly after the Pirates traded the right-hander to the Rays on June 2 for shortstop prospect Alika Williams.

A few weeks into his time with Tampa Bay, Stephenson had a conversation with Kyle Snyder. The Rays’ renowned pitching coach mentioned a couple tips, Stephenson said, related to the positioning of his hand on the ball and the mentality behind it.

“It kind of worked out,” Stephenson said. “Something clicked for me, and I was able to do it.”

So, how long did that change take?

“To be honest, the day he mentioned it was the same day I adjusted it,” Stephenson said, smiling. “So, it was a quick fix. … I don't know, something he said to me just made sense.”

Just like that, in mid-June, Stephenson’s heavily used breaking ball transformed from an 83-85 mph offering with some horizontal sweep into this 88-90 mph offering with more vertical moment. He also throws a fastball in the upper 90s and a splitter to keep left-handed hitters off-balance, but the slider remains his primary weapon.

“Predominantly, that's what he's going to go to. I'm just amazed that, like, the hitters know that, too -- and the results that he has gotten have been really, really impressive,” manager Kevin Cash said. “It's as wipeout of a pitch as we've seen, basically, since we acquired him.”

Indeed, the pitch has yielded a .083 opponents’ average and a 59.5 percent whiff rate since he introduced it. Statcast classifies the harder breaking ball as a cutter, differentiating it from his old breaking ball, but Stephenson still refers to it as a slider. Whatever you want to call it, it’s made him into another legitimate late-inning weapon for Tampa Bay.

“Exceptionally impressive,” GM Peter Bendix said recently. “The results have been incredible. Just to have another guy who can come in and get righties out and lefties out, come in and just throw strikes, he can miss bats at a really nice pace -- it just helps stabilize things.”

After posting a 5.14 ERA, 1.43 WHIP and 2.13 strikeout-to-walk ratio in 18 appearances with the Pirates to begin the season, he’s put together a 2.93 ERA, 0.72 WHIP and 6.00 strikeout-to-walk ratio with the Rays, with a whiff rate that still ranks among baseball’s best since the trade.

What’s changed?

“The first thing is trusting the approach that these guys instill in us. I think that's been a huge part of the success I've had since I've been here,” he said. “Then also just tinkering with my slider a little bit, adding a little velo to it, I think that's helped a lot. So, combination of those couple things, and really just trusting the catchers we have back there.”

The approach Stephenson mentioned is a simple one that’s helped many pitchers improve with the Rays: trust your stuff, do what you do best, attack the zone and throw strikes. He’s taken to that strategy as well as he’s fit in with the group of Rays relievers who call him “Bob” and never hesitate to joke about his unfailingly well-coiffed, blow-dried and styled hair.

“It is impressive hair,” Pete Fairbanks said.

Impressive pitching, too.

“Bob Stephenson has been unbelievable,” Fairbanks said. “I mean, you can tell them [the slider is] coming, but it's still not an easy pitch to hit. You couple that with his ability to hide the ball, and then he's got a plus splitter and he throws his fastball pretty hard, too. That's a combo to get a lot of swings and misses.”