Yankees Bolster Their Rotation with Luis Severino

The Yankees rotation is looking rather thin these days. After losing Michael Pineda to a forearm injury, the team was left with a gaping hole in their rotation behind Masahiro Tanaka, Nathan Eovaldi, Ivan Nova and CC Sabathia. Even before Pineda’s injury, the team already had a hole at the back of their rotation in Sabathia, whose days as a productive pitcher appear to be well behind him. Overall, that’s an underwhelming rotation for team that’s likely headed to the playoffs.

Somewhat curiously, the Yankees didn’t acquire any rotation help at the trade deadline. Even more curiously, it doesn’t seem like they made much of an effort to do so. Instead, they seemed more interested in fortifying the back of their bullpen, which is already one of the best in baseball.

The imminent arrival of top prospect Luis Severino may have been the primary reason for the Yankees’ inaction. Minutes after the non-waiver trade deadline had passed, Brian Cashman revealed the 21-year-old’s next start would be in the big leagues. He debuts tonight against the Red Sox.

Severino has little left to prove in the minor leagues. The hard-throwing righty split time between Double-A and Triple-A this year, where he recorded FIPs of 2.34 and 2.53, respectively. Severino was similarly dominant last season, when he rattled off a 2.46 ERA and 2.46 FIP across three minor league levels: Low-A, High-A and Double-A.

Severino’s faced very little resistance in his ascent to the majors, especially for a guy who signed out of the Dominican with little fanfare. However, once he reached the Triple-A level, he didn’t miss as many bats as he did in the low minors. Severino posted strikeout rates of 25%, 35% and 30% in Low-A, High-A and Double-A, respectively, but struck out just 21% in Triple-A.

This trend is a mildly concerning one, as a pitcher’s propensity to strike batters out is a rather strong predictor of big league success. However, it’s comforting to see that Severino’s other metrics remained excellent. His walk rate barely budged, and he didn’t allow a single homer in his 11 starts at the Triple-A level.

Let’s look a bit more closely at Severino’s home run numbers. Although he’s not much of a ground ball pitcher, Severino does a good job of limiting the damage on the balls hit in the air against him. For one, he induces more than his share of infield flies. According to Minor League Central, Severino’s infield fly ball rate was higher than his league’s average at every stop since High-A. But more importantly, his home run to outfield fly ball ratio has been consistently lower than league average. Between this year and last, just 4% of Severino’s fly balls to the outfield have left the park, compared to an average of roughly 8%. All of this is to say that Severino doesn’t allow a ton of hard contact.

KATOH is enamored with Severino. Based on his 2015 numbers, my system forecasts him for a remarkable 12.5 WAR through age-28, which would have made him the 5th highest ranked prospect in the preseason, and the highest ranked pitching prospect. His forecast represents a sizable increase from the 7.2 WAR mark yielded by his 2014 numbers. Simply put, very few 21-year-olds dominate the high minors like Severino did.

Let’s pull up some comps. Using league-adjusted, regressed stats, along with age, I calculated the Mahalanobis Distance between Severino’s 2015 stats and every season at Triple-A 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 Severino’s, ranked from most similar to least similar.

Rank	Mah Dist	Name	IP thru 28	WAR thru 28
1	0.49	Julio Teheran*	564	6.8
2	0.81	Barry Zito	1,430	23.4
3	0.84	Liam Hendriks*	235	1.1
4	1.11	Bill Pulsipher	323	1.2
5	1.17	Charlie Haeger	83	0.0
6	1.18	Brad Halsey	286	2.3
7	1.37	Jason Schmidt	949	13.3
8	1.49	Livan Hernandez	1,449	19.2
9	1.63	Grant Roberts	101	1.0
10	1.67	Tom Gorzelanny	663	6.5
11	1.70	Jeanmar Gomez*	401	1.0
12	1.71	Nick Kingham*	0	0.0
13	1.71	Howard Farmer	23	0.0
14	1.72	John Lackey	1,161	23.3
15	1.93	Allen Levrault	170	0.0
16	2.00	Dylan Axelrod	216	0.0
17	2.03	Randy Keisler	67	0.0
18	2.05	Chad Gaudin	670	3.3
19	2.07	Mike Williams	398	1.2
20	2.16	Matt Murray	14	0.0

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

Of course, many of these pitchers’ stuff wasn’t anywhere near as good as Severino’s. Let’s thin the field a bit to weed out all of these non-prospects. Here’s a look at the guys who were either drafted in the first round or cracked Baseball America’s top 100 list the winter before their Severino-esqe seasons.

Rank	Mah Dist	Name	IP thru 28	WAR thru 28
1	0.49	Julio Teheran*	564	6.8
2	0.81	Barry Zito	1,430	23.4
4	1.11	Bill Pulsipher	323	1.2
7	1.37	Jason Schmidt	949	13.3
8	1.49	Livan Hernandez	1,449	19.2
9	1.63	Grant Roberts	101	1.0
10	1.67	Tom Gorzelanny	663	6.5
12	1.71	Nick Kingham*	0	0.0

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

Severino finds himself among some mighty fine company. Barry Zito, Jason Schmidt and Livan Hernandez were each among the best pitchers in baseball for a time, and they performed a lot like Severino before they broke into the big league scene. Bill Pulsipher might have wound up in that category too had he not hurt his elbow as a 21-year-old. Even Julio Tehran and Tom Gorzalanny turned into quality big leaguers. The Yankees would obviously hope for a little more from their top prospect, but a career resembling Julio Tehran’s — who’s still only 24, by the way — wouldn’t be the worst outcome in the world. Simply put, the statistical comps agree with KATOH on Severino: He looks excellent.

So those are Severino’s numbers. They’re unequivocally great, and bode very well for the righty’s future. Few 21-year-olds have accomplished what Severino has this year. And among the few who have, several have carried their domination over to the highest level.

But numbers are only numbers. It’s also important to know how Severino’s produced those numbers. In terms of stuff, there aren’t many pitchers who can match the type of heat Severino brings. He sits in the mid to high 90s with his fastball, leading Kiley McDaniel to give the pitch a FV of 70 in the preseason. Severino’s second best pitch is his changeup, which flashes plus. His slider is still a work in progress, but according to Kiley, he’s managed to be a bit more consistent with the pitch of late. However, since this was an improvement Severino was expected to make, it wasn’t enough to bump his FV up from the 60 grade in the preseason.

Based on everything I’ve said above, Severino has the looks of a very exciting prospect. But don’t just take my word for it. The 21-year-old got lots of love from evaluators in midseason re-rankings last month. Baseball America, Baseball Prospectus, John Sickels and MLB.com had him 17th, 28th, 16th and 16th, respectively.

Keith Law, however, didn’t include the 21-year-old in his mid-season top 50 list. His merely listed his name among the honorable mentions. He also left Severino off of his preseason top 100. Keith is a smart guy who really knows his stuff, so when he deviates from the industry by such a wide margin, we should certainly take notice. Here was Keith’s reasoning for the low ranking, which he laid out in a chat last winter:

Severino is a future reliever. You can’t stay a starter without using your lower half at all. He has a great arm, loose and easy, but I can’t name an MLB starter who uses his lower half as little as Severino does – nor do I think you can truly command your fastball if you’re all arm and no legs.

Does Severino’s unorthodox delivery really dampen his chances of hacking it as a starter? Possibly. That’s not a question I’m particularly qualified to answer. From a purely statistical standpoint, though, he’s dominated in the upper levels of the minors; and I’m hesitant to think pitching as a starter in the big leagues is that much different than doing so in Triple-A. But if there’s a reason to be worried about Severino, this is probably it. And his 5.2 innings per start in the minors this year does little to belie Law’s “future reliever” label.

Mechanical concerns aside, Severino has an awful lot going for him. Not only does he have tremendous stuff, but he has the statistical track record of a pitcher with star potential. As with all pitching prospects, his fulfilling that potential is far from guaranteed. But it’ll be exciting to watch him scratch the surface the next couple months. And if things go well, he very well might wind up throwing some important innings for the Yankees come October.