DENVER — In the span of five minutes, Arizona Diamondbacks pitching coach Brent Strom referred to starting pitcher Zac Gallen as a unicorn and decathlon champion.

Yes, judging from those descriptions, there's something special in Strom's eyes about Gallen, who is the current leader among MLB.com voters to win the National League Cy Young Award. A pitching coach who has worked with pitchers such as Gerrit Cole and Justin Verlander during his time with the Houston Astros and now guides Gallen and Merrill Kelly as the leaders of the Arizona rotation, Strom sees something in Gallen that he hasn't seen before.

"His ability to throw the ball low and away, which is very difficult from that angle, it's simply freakish to be honest with you," Strom said. "Of all the pitchers I've had, I've never had anybody with as good of a command and as good of a spin on four different pitches than he has. I've had guys that have had better fastballs. I've had guys that have had better curveballs. I've had guys that have had better changeups. I've had guys that have had better sliders, but nobody that has had all four. He's kind of like, for me, a decathlon champion with a lot of skills."

Those skills are part of the reason why Gallen has become a must-watch pitcher when he takes the mound, including Thursday night in San Diego when he will open a critical four-game series for Arizona against the Padres. With those two teams battling for Wild Card positioning, Gallen will look to improve on a season where the 28-year-old right-hander is seventh among all MLB pitchers in bWAR with 3.5 and eighth in WHIP at 1.066.

Analytics and deception key part of success for Zac Gallen

Part of the reason for Gallen's success? His analytical approach to the game, which includes an obsession for pitch sequencing and spending hours before a start digging through everything he needs to know about his opponents for that day, even if he's seen them plenty of times in the past.

"No matter if you've seen a guy five times or if you've seen him 25 times, you run that fine line of, 'Okay, so how much credit do I give the hitter?' Hitting is hard and, as a pitcher, you always have the advantage. You kind of toe that line of, 'How have I gotten them out?' See what they're doing, what they're struggling with, or what they're excelling at and try to mesh it all together.

"Then, as the game goes on, you can kind of get a sense for the most part what guys are trying to do to you, so you just try to incorporate that as well."

With every game being a chess match between Gallen and the batter, fellow Diamondbacks starter Merrill Kelly believes it is the minute details and discipline to do the prep work ahead of time that sets Gallen apart.

"We have a lot of the same interests and we think about pitching a lot of the same ways," Kelly said.

"He's a little bit more analytical. He's a little bit more precise in what he does. You know, he really enjoys dialing in the minute details of feel and his hand positioning and everything like that. He dives a little bit deeper in the details than I do in the way that I operate."

Gallen says those details are part of a constant evolution that he has undergone from the time he first loved baseball as a child and continued through his time at the University of North Carolina and a pair of trades that took him from the St. Louis Cardinals to the Miami Marlins before finally finding a home in the desert with the Diamondbacks.

"Once I got to college and playing the field wasn't a thing anymore, I dove in on pitching," Gallen said. "It started from there, starting on the delivery side and picking up the cutter/slider. I learned how to manipulate that, and then the curveball was when I got to pro ball. I started learning that. The changeup, as a kid, I didn't know why it worked. It just worked, but I had to kind of relearn it over the last couple of years and what makes it tick.

"For me, it's more of an obsession with pitching and understanding how things work. I'm kind of obsessed really is what it boils down to."

That obsession has pushed Gallen into a different tier, with Strom saying the arm slot that Gallen uses combined with his ability to place the ball makes him an elite hurler.

"Control and command is number one, but the fact that he's not conventional, he's a little bit of a unicorn in the way that hitters view him," Strom said. "It's one of the misunderstood things in pitching is the ability to quantify deception. It's not something that is easily is not easily done on a computer."

Kelly calls Gallen's art on the mound a bit of deception.

"Any time that you can look at a guy like him who obviously is so good at what he does, and is so disciplined in his craft, and is able to manipulate the ball the way he does, it's been fun for me to be able to pick his brain," Kelly said.

While Gallen has evolved into a dominant force, he believes evolution is a constant as a pitcher.

"You're not necessarily the same person you were five years ago, just because your stuff changes, whether it be velo drops or increases or movement or any of that type of stuff," Gallen said. "For me, it's just being able to give hitters different looks and not fall into a pattern. For me, you have to keep improving or keep adding something or take something away, whether it's usage or you're trying to manipulate a pitch or whatever it is. You don't get to rest on your laurels."

What's the next evolution for Gallen? It's hard to say, but it's something that MLB hitters should already be sweating.