PEORIA, Ariz. -- Tyson Ross rocks into his windup, his commanding 6-foot-6 frame made more imposing by the pedestal of dirt he stands upon. He starts with a high leg kick and follows with a short stride toward the plate. He brings his arm back deliberately, then violently snaps it forward, letting go of the baseball.
To the opposing hitter, it's undeniably a fastball for 90 percent of its trajectory toward home plate -- a fastball with one of the sharpest bites in the league, mind you. And just when it's time for that hitter to commit and swing at the fastball, the bottom drops out.
"It's the best slider I've seen," said catcher Austin Hedges, who backstopped Ross 17 times last season. "It's No. 1 in my opinion. It's a fastball for so long. For it to move that much, that late, there's really no explanation for how he can make a pitch do that."
"It's a devastating pitch," said Padres manager Andy Green. "There's very few in the game that have something that works that effectively to end at-bats against righties and lefties. It's right at the top of the game in my mind, and I'm not in the minority."
For practically his entire baseball life, Ross has been throwing the slider. He learned it when he was 11 years old, playing Little League ball in Oakland, and hasn't stopped throwing it since.
"It just kind of worked with my arm slot, and it came natural to me," Ross says. "Over the years, I've thrown thousands of them. Just with those repetitions and figuring out how it comes out of my hand and how it spins, it's just grown over the years."
It's grown into one of the sport's most prodigious pitches. Of Ross' 212 strikeouts last season, he finished off 149 with the slider, according to Fangraphs. Throughout his career, opponents are hitting an anemic .197/.251/.269 against it.
So what makes the pitch so tough?
"As far as movement goes, it's never the same," said Derek Norris, the man who will catch Ross for the season opener against the Dodgers on Monday. "It's never the same break -- I think the randomness of the pitch has more effect than the actual pitch itself."
In essence, that one pitch plays the role of three -- cutter, slider and curve -- along with all the gray area in between. Ross reiterates that he doesn't have as much control over the precise arc of the pitch as people think. But Norris counters by saying that the unpredictability might make it even more dangerous.
To be clear: Ross is much more than a one-pitch pitcher. His sinker induces some of the weakest contact in baseball, most of it on the ground. (Ross had a 68 percent ground-ball rate with the pitch last season.) He also possesses a changeup that he has used to great success against left-handed hitters.
But Ross' arsenal isn't anything new. When he went 6-18 with a 5.33 ERA in three seasons with the A's, he was throwing those same pitches.
The Padres traded for Ross in November 2012, giving up Andy Parrino and Andrew Werner. It was the fresh start Ross had been looking for.
"I struggled big-time in Oakland, was really inconsistent," Ross said. "I came to San Diego [and got] the chance to work with [pitching coach] Darren Balsley, who's had so much success as far as getting pitchers back on track.
"They believed in me, gave me a chance to start here. It was just a clean slate overall, and it was a great opportunity for me. I just told myself I'm going to work hard and make the most of it and see what happens."
What happened was a career rebirth. In three seasons with the Padres, Ross owns a 3.07 ERA and has allowed just 7.6 hits per nine innings. If he can reduce his walk rate, some are mentioning Ross as a fringe Cy Young candidate.
Balsley thinks Ross is already a top-five pitcher in the National League -- with room to grow. How exactly did Ross get to that point from the shaken, struggling hurler who came over from Oakland?
"Confidence doesn't hurt," said Balsley. "It wasn't that he didn't have any confidence before, but now he knows he's good, and he expects to go out there and dominate. He pretty much knows that if he throws well, he's going to dominate the baseball game."
Confidence. And one of the nastiest sliders in the sport.
"I'm biased," said Balsley when asked where Ross' slider ranks, before pausing for effect. "It's probably the best."
AJ Cassavell is a reporter for MLB.com. Follow him on Twitter @ajcassavell. This story was not subject to the approval of Major League Baseball or its clubs.