The Phillies rotation has been pretty terrible this season. Well, the Phillies in general have been pretty terrible this season, but their rotation has been especially bad, particularly when Cole Hamels hasn’t pitched. If you take away Hamels’ innings, Phillies starters have a 5.86 ERA for the season. 5.86! Collectively, this group has been worth -0.3 WAR and -5.0 RA9-WAR.

It’s been ugly. But fortunately, the Phillies are adding some much-needed pizzazz to the non-Hamels division of their rotation. Aaron Nola, the team’s seventh-overall pick from the 2014 draft, will take over one of the spots in the team’s rotation. He’ll make his big-league debut tonight at 7pm ET against the Tampa Bay Rays. Nola was a consensus top-15 prospect on this year’s recent mid-season prospect lists.

As is the case with most first-round college pitchers, Nola’s ascent through the minors was a rapid one. Since the Phillies plucked him from LSU’s rotation in last year’s draft, he’s played all of 30 games in pro ball — 12 this year and 18 last year — totaling 165 innings.

After signing him to a $3.3M bonus last June, the Phillies started Nola off in High-A. He wasn’t there long, though, as they promoted him to Double-A after just 31 innings of 3.16 ERA ball. He was slightly less dominant in his late-season stint at Double-A, where he saw his strikeout rate plummet from 25% to 15%. However, he mastered the Double-A level in 2015, when he pitched to a 1.88 ERA and 2.87 FIP in 12 starts.

He was similarly dominant in his six-start pit stop in Triple-A this year. Well, he was dominant up until his most recent start, where he got shelled for five earned runs in three innings. Prior to his final start, he held a sparkling 1.90 ERA and 2.33 FIP, but jumped to 3.58 and 3.17 afterwards.

All told, Nola ran a 2.57 ERA and 3.35 FIP in his minor-league stay. His strong performance was due in part to his solid 21% strikeout rate, which was a notch above the average minor leaguer. But Nola’s calling card is his excellent command, which shows up in his sterling 4% walk rate. He also did a fine job of keeping the ball in the park with just 15 homers allowed in 30 games.

Nola relies on three pitches to get hitters out: a fastball, a curveball and a changeup. Each of these three pitches is at least average right now, according to Kiley McDaniel, and each also flashes plus. This evaluation bodes very well for the Nola’s future development, as pitchers who can command three plus pitches are simply few and far between.

Nola has been one of the best performers in the high minors this year at the tender age of 22, so it’s no surprise that KATOH’s a fan of his work. My system pegs him for 5.1 WAR through age-28, which would have made him the 12th-highest-ranked pitcher in the preseason (61st overall). In other words, KATOH agrees with the scouting consensus that Nola is an upper-echelon pitching prospect.

Let’s get some comps up in here. Using league-adjusted, regressed stats, along with age, I calculated the Mahalanobis distance between Nola’s 2015 stats — between Double-A and Triple-A — and every season at those two levels since 1991 in which a pitcher faced at least 350 batters. Below, you’ll find a list of historical players whose performances were nearest and dearest to Nola’s, ranked from most to least similar.

*Pitchers who have yet to play their age-28 seasons.

There aren’t a bunch of stars her, but there aren’t too many flops, either, especially near the top of the list. James Baldwin, John Lackey, Shawn Estes and Barry Zito were all very successful starters, while Ryan Madson, Zach Britton, Dana Eveland and Gabe White were quality bullpen arms. Bill Pulsipher and Jarrod Parker likely would have followed similar paths had they managed to stay healthy. It’s also probably fair to throw out comps like Jason Young, Mike Smith and John Ely (and possibly others from the pre-PITCHf/x era) — who didn’t throw nearly as hard as Nola, who sits in the low- to mid-90s with his fastball — making this list all the more encouraging.

Given his excellent minor-league track record, there’s little doubt that Nola is ready for the big leagues. In fact, as Nathaniel Stoltz noted last summer, he was probably ready to contribute in some capacity when he threw his first pitch as a professional. Now that he has a year of minor-league seasoning under his belt, it’s just a matter of adjusting to the game’s highest level.

As of this writing, the Phillies have a 32-62 record, which is to say they won’t be playing anything resembling meaningful baseball from here on out. As a result, Nola will have the opportunity to make his transition in a relatively low-pressure atmosphere, where he’ll have plenty of leeway should he for some reason struggle early on. It’s doubtful he’ll need this luxury, though. Given his success in the high minors, there’s little reason to think he won’t be good right away. And he stands a good chance of being one of the game’s premier pitchers in a couple of years.