The Pirates have a top right-handed pitching prospect on their Opening Day roster … but it’s not the one everyone has been focusing on.

Don’t worry, Buccos fans, Paul Skenes will come soon enough. The even better news is he’s not the only really good arm at the top of the system. Jared Jones, the Pirates' No. 3 prospect and MLB's No. 60, will get the first look at the big league rotation, making the team after not allowing an earned run over 16 1/3 innings in Grapefruit League action.

He’ll make his first Major League start in Miami on Saturday, and it’s not an exaggeration to say that of all the top pitching prospects in this system (there are four Top 100 arms here after all), nobody has evolved as much as Jones has since joining the organization. He transformed from a “thrower” to the complete pitcher who wowed staff and fans in Bradenton this spring.

• MLB Pipeline | Top 100 prospects | Prospect video

As a high school senior in 2020, Jones had a reputation as being a pure power guy, both on the mound and at the plate. He could hit homers, but it became clear that his future would be as a pitcher after blowing hitters away at showcase events, like the inaugural PDP League in the summer of 2019. It was there he told me that he tried not to overthrow (not always successfully) and liked getting strikeouts with his slider more because he liked “seeing knees buckle.”

Some things haven’t changed, though he now has two distinct breaking balls -- an upper-80s sweeper and low-80s curve with depth. He can really spin both, and he’s buckled many knees with a 38 percent miss rate on his breaking stuff across Double-A and Triple-A in 2023. He featured his slider more this spring and produced a 59 percent miss rate with the pitch, albeit in a small sample size.

Some things have changed a lot. He still throws plenty hard, averaging 97 mph with his fastball in Grapefruit League action, while touching triple digits. That wasn’t a Spring Training mirage: His fastball averaged 96.2 mph, according to Synergy, in the Minors in 2023 and also topped out at 100 mph. It has high spin and high ride up in the zone. But he’s learned along the way that he doesn’t have to overthrow to miss bats. He did so at a 29 percent rate with his heater in 2023 while commanding it better than he had previously. His strike-throwing has been on a steady progression, from walking 4.6 per nine in his first full season to 3.7 in 2022 and then 3.6 last year (3.2 in his ten Double-A starts before getting promoted to Triple-A).

Greensboro, the Pirates’ High-A affiliate, can be brutal for pitchers. It’s a hitter’s park and popups can turn into home runs in a hurry, especially if the wind is blowing out. You might look at Jones’ 4.62 ERA and 19 home runs allowed and wonder how that’s considered progress, but having to pitch an entire season there might have been just what the doctor ordered.

In the very early stages of his career as a teenager, Jones’ biggest obstacle was himself and his own maturity, or lack thereof. Learning how to keep his competitive fire in check has taken some time, and pitching in a place like Greensboro, you’re forced to really lean into recognizing what things are out of your control. The Pirates saw a marked difference in his mentality when he came to big league camp a year ago, and it translated into the 2023 season he had that brought him to this point.

As much as he’s worked to harness his impressive stuff, he’s also refined it while showing more ability to make adjustments than he did when he first entered pro ball. Case in point was a stretch in Triple-A last year when he was overthrowing his slider. The sweet spot for the pitch is really in the 88-92 mph range, but he was overthrowing it with Indianapolis, up to 92-94 mph, turning it into a less successful cutter-like pitch.

He dedicated himself to really executing the pitch during the offseason, and that’s what was on display all spring, a potentially plus out pitch. And it’s not like he’s given up on the development of his curve and changeup, with a good chance at having a true four-pitch mix.

Remember, he’s only 22. Just because he’s reached the big leagues does not mean he’s even close to being done developing, and it might be a year or two before the Pirates know exactly what kind of pitcher Jones can be. One thing that’s still to be determined is if he can hold up over the course of a full Major League season. His fatigue rates haven’t always been great, though they’ve improved. If he can show that he can maintain his stuff over 150 innings, then he’s at least a No. 4 starter, with the hope that he can build from there.

Jones came into camp with a little chip on his shoulder, wanting to prove to everyone that he can start for a long time. So don’t be surprised if he continues to evolve and quash any questions about his ability to stick in a big league rotation for a long time.