With only 10 Cactus League games in the books, it is too early to declare a winner for the Diamondbacks’ fifth starting rotation spot. But, based on the numbers, two youngsters have already separated themselves: right-handed flamethrower Drey Jameson and top pitching prospect Brandon Pfaadt.

In two starts, Jameson has pitched four scoreless innings, allowing just one hit and one walk with three strikeouts. Pfaadt has pitched five scoreless innings in his two appearances, allowing just two hits and two walks with six strikeouts. By comparison, fellow rotation candidates Tommy Henry and Ryne Nelson have struggled mightily.

Let’s not get ahead of ourselves, though. Pitchers often throw more than 20 innings in the Cactus League. At the moment, no Diamondbacks pitcher has thrown more than five. If, say, Henry throws four scoreless innings next time out and Jameson or Pfaadt struggle, the calculus could change quickly.

It should also be noted that there is more to the D-backs’ fifth starter battle than the box scores. D-backs manager Torey Lovullo made that clear on MLB media day back on Feb. 15.

“It’s not gonna be the results,” Lovullo said. “You get guys that flash zero earned run averages for six innings. It’s about the reps. It’s about the consistency of those reps. And it’s about the consistency of execution.”

For pitchers, spring training often functions as a testing ground for new pitches or altered mechanics. Game plans can be more geared at mastering certain pitches in certain locations rather than simply getting hitters out. As a result, just because the box score doesn’t look good doesn’t mean Lovullo and his staff do not like what they see. Conversely, just because the box score does look good doesn’t mean Lovullo and company do like what they see.

Even so, neither Jameson nor Pfaadt’s sparkling Cactus League stats seem misleading. They have both consistently — in albeit a small sample size — executed quality pitches with decent command from the get-go.

When asked what he has been most pleased with so far, Jameson mentioned his sinker and his ability to limit walks.

“Executing my sinker [to] both sides of the plate,” he said. “And, honestly, just staying in the zone, eliminating walks. My last outing, I had one walk. Still working on that front-hip sinker. And, I mean, just going out and competing.”

Jameson’s sinker has been a key weapon since he learned the pitch from former Diamondbacks pitcher Matt Peacock two years ago.

“It’s very important,” Jameson said. “Four-seam to the top of the zone lets me have that sinker to the bottom of the zone. And, when I get in trouble or behind in counts, I rely on that sinker to get me that ground ball, soft contact.”

That strategy worked well for Jameson in his most recent start, which happened on Wednesday against the San Francisco Giants. Three out of the four balls in play against him were ground balls. He also struck out two and induced a fly-out, and he retired all six batters that he faced.

As for Pfaadt, he admitted that he was a “little antsy” in his first outing of spring training, but he felt more comfortable on Saturday, throwing 25 of his 39 pitches for strikes.

“I think I got the first one out away,” Pfaadt said. “I feel like each time we go out there and kind of develop that routine, it’ll get easier.”

Pfaadt has made it look relatively easy in both of his appearances, allowing just four total baserunners in five innings. The Diamondbacks defense has also played a significant role, catching two would-be base stealers and turning a double play. The latter of those stolen base attempts would have been successful had it not been for a crafty play by second baseman Ketel Marte that baited Tim Lopes off the bag.

Said Pfaadt: “I was like, ‘Thank God.’ At first, I didn’t really know what happened. I was like, ‘Wait, he’s out? That’s pretty cool.'”

Pfaadt has relied primarily on his four-seam fastball and slider in his two outings, throwing them a combined 79 percent of the time. He has also mixed in a handful of changeups and curveballs.

Carson Kelly has been behind the dish for both of Pfaadt’s Cactus League starts. Kelly had previous experience with Pfaadt, having caught him in a rehab assignment for High-A Hillsboro back in 2021.

“It’s really a joy to catch him,” Kelly said. “He’s fearless. I think that’s the thing with guys, especially young guys, when they come up … and they try to nibble and they’re not really attacking guys.

“He’s done a really good job by just filling up the zone and and then late getting guys to chase.

“I think he’s going to be a really good major league pitcher for a long time.”

When asked whether Pfaadt has put himself in the middle of the fifth starter race, Lovullo was noncommittal.

“He’s doing exactly what we hoped he would do,” Lovullo said. “I don’t know where it lands with all of our young starting pitchers. I just know we got a lot of good ones. And it’s going to be a lot of fun. It’s going to be fun to watch. We’re going to have a tough decision to make.”

It is possible that, all other things being equal, the team would favor Jameson over Pfaadt simply because Jameson has already pitched in the majors. Despite that potential advantage — and how good he has looked so far — Jameson isn’t counting on anything just yet.

“At the end of the day, it’s out of my control what happens,” Jameson said. “It’s in my control what happens on the field, but off the field and decision-wise, it’s not in my control. So, I just go out there, I do what I need to do to the best of my capability. Whatever happens happens.”

On paper, Pfaadt and Jameson have already set themselves apart in the early-goings of the D-backs’ fifth starter battle, but there is still plenty of Cactus League action to play. Regardless, whether Pfaadt and Jameson open the year in the big leagues is not season-defining. Injuries to the big-league rotation are inevitable. Both will get their chance eventually. And it sure looks like they’ll be ready when the time comes.

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