Dominic Leone shores up St. Louis Cardinals bullpen

Last Friday, the Cardinals traded displaced outfielder Randal Grichuk -- an exciting but undeniably inconsistent power bat -- to the Blue Jays for major league reliever Dominic Leone and minor league pitching prospect Conner Greene (our own Kyle Reis spoke about Greene a bit here; and I hope to have more later). Essentially, a bullpen loaded with question marks entering the offseason has effectively been shored up by the additions of (likely fifth starter) Miles Mikolas, Luke Gregerson, and Leone. Sure, I may have preferred other moves to have been made (i.e. Juan Nicasio, Addison Reed) over Gregerson, but at least the organization did not bite on an overpriced closer on the verge of decline (i.e. Greg Holland, Wade Davis).

Pitching in the American League West, the National League West, and the American League East (for three teams over three MLB seasons), Cardinals fans were likely unfamiliar with Leone prior to the Grichuk trade being announced. Admittedly, I knew very little about the 26-year-old reliever as well. However, as this site's self-proclaimed pitching analyst, I just had to learn more about the Cardinals' new arm. While I may have been disappointed in the Cardinals for passing on enticing arms in Nicasio and Reed, upon further review, the Leone addition has me downright giddy for the 2018 season. Let me explain, and if my explanation isn't enough, @cardinalsgifs' visuals will certainly do the trick.

Career statistics

Leone's success in 2014 is not all that surprising as it takes some time (even longer for a reliever) for opposing teams to develop a reliable scouting report (or "book") on a new pitcher. However, when that "book" is finally established, the early success can be short-lived, as shown by Leone's poor numbers in 2015 and 2016. Yet, in 2017, Leone appears to have reinvigorated his career, posting an fWAR that placed him on the first page of the reliever leaderboard. After two below replacement level seasons, what changes did Leone make? Are these changes repeatable? Or did Leone merely experience positive results during the typical swings of reliever volatility?

2017 repertoire (via BrooksBaseball)

Remember, regarding horizontal movement in right-handed pitchers, a negative value means arm-side movement, whereas a positive value means glove-side movement.

For a reliever, Leone possesses a fairly deep repertoire. While he is primarily fastball-cutter (80.78%), all four pitches worked for him last year. In terms of pure swing and miss quality, the slider was his most prolific pitch in 2017 -- yielding whiffs on 60.42% of swings. This was a significant jump from years prior when the pitch led to whiffs on 37.66% of swings. While the cutter's whiffs per swing rate (44.66%) wasn't quite as high as his slider's, it, too, eclipsed the rates of prior seasons. When you take into account how frequently Leone throws the cutter, this swing and miss rate is even more impressive,

And for those interested in individual pitch results, I have included them below. As always, do not put too much stock in individual pitch results as they do not tell the whole story. However, when there exists a disparity like the one seen between 2015-2016 and 2017, the results are certainly worth noting.

So, what happened to these two pitches? Why did they all of a sudden induce significantly more whiffs and also lead to better batted ball results? Before getting into the two pitches specifically, I must first note that Leone really buttoned up his release point last season. As you can see in the "2017 repertoire" table, the largest difference between any two of his pitches was 0.08 feet, or 0.96 inches. While there wasn't much of a disparity in years prior (the largest in 2015-2016 was 0.12 feet or 1.44 inches), cleaning the release points up to a less than one-inch difference is vital from the perspectives of pitch tunneling and sequencing.

Cutter development

Bottom line, the 2017 cutter was different than the 2015-2016 version. On average, Leone threw it a bit softer (88.95 MPH versus 89.74 MPH), induced slightly more horizontal movement (2.16 inches versus 1.63 inches), and exhibited a higher spin rate (2,486 RPM versus 2,378 RPM). These changes, particularly the increase in horizontal movement -- to his glove-side -- allowed for a shift in the pitch's core -- outward to righties and inward to lefties (into a perfect swing and miss zone; leaguewide, 52.6% of swings led to whiffs on cutters in this zone). While the 2015-2016 core wasn't by any means bad, the 2017 one was even better at yielding weak (or often, as detailed above, zero) contact.

Keeping in mind the inherent differences between the two versions, courtesy of the great @cardinalsgifs (he really outdid himself with these .gifs), I have embedded .gifs of a cutter that yielded a bad result and a cutter that yielded a good result. Both pitches were thrown to an identical location -- middle-up, on the outside corner.

Admittedly, it's not exactly a fair comparison as Tyler Flowers (career wRC+ of 94) is a superior hitter to Adeiny Hechavarria (career wRC+ of 72). But, as you will see by the pitch trails, the 2017 cutter had clearly more bite on it than the one from 2016. Heck, and this is a bit of an illusion due to the left-center camera angle, but the 2016 cutter backed up at the end, while the 2017 version had distinct glove-side break throughout its flight.

Bad cutter from 2016