Pitch Analysis: Alexis Díaz
(3/9/23) Alexis Díaz has the potential to earn quite a few saves this season, and could be an attractive trade target at the trade deadline.
Originally published on Medium on March 9, 2023.
Nearly three years removed from their last playoff appearance, the Cincinnati Reds appear to be heading towards another rebuilding season in 2023. One of the few bright spots in Cincinnati this season will be the further development of their exciting young starting pitchers, such as Nick Lodolo, Hunter Greene, and Graham Ashcraft. Another exciting young pitcher in Cincinnati that has been overlooked is Alexis Díaz, who projects to be the Reds closer this season. The brother of New York Mets closer Edwin Díaz, Alexis has a similar pitch arsenal to his older brother (Fastball-Slider), however he has experienced more command issues than Edwin has over the course of his young career. With further development to his pitch arsenal, Alexis Díaz has the potential to earn quite a few saves for the Cincinnati Reds this season, and could be an attractive trade target for contending teams at the trade deadline.
Overview:
As shown by the tables above, Alexis Díaz possesses two pitches in his pitch arsenal, a Fastball and a Slider. According to my Stuff+ model, both pitches are rated as above-average, and this is backed by the high amounts of Whiffs and low xwOBA that Díaz is able to produce on these two pitches. Díaz throws both his pitches with plus velocity, and according to Baseball Savant, the Slider is above league-average in both horizontal and vertical movement.
In 63.2 IP last season, Díaz pitched to an 1.84 ERA with a 32.6% strikeout rate, while earning 10 saves for the Cincinnati Reds. Two points of concern regarding Díaz’s performance last season was his high walk rate (12.9%), and his extraordinarily low BABIP allowed (.181) which almost certainly will regress to the mean next season. In addition, there seems to be a significant discrepancy in how valuable Díaz was last season between Baseball-Reference and FanGraphs’s WAR metrics, as Díaz produced a 3.1 bWAR and a 1.0 fWAR in 2022. A deeper dive into Díaz’s pitch arsenal is necessary, in order to determine how valuable he is to a Major League bullpen and to identify areas in which he can improve upon in the future.
Four-Seam Fastball:
As shown by the tables above, Alexis Díaz throws his Four-Seam Fastball more often to left-handed hitters than right-handed hitters. While he has difficulty locating this pitch in the strike zone, as evident by a below-average Zone Rate, Díaz is able to generate a lot of Whiffs in the strike zone with his Fastball, especially against RHH. With an elite vertical approach angle of -3.6 degrees, Díaz’s Fastball is able to dominate when thrown at the top of the zone, and he consistently executes this approach against both left and right handed hitters. Díaz is able to induce ground balls at a league-average rate against RHH, but struggles to do so against LHH. Overall, Díaz utilizes his Fastball at an expected frequency for a pitch that is arguably the best in his arsenal, however I do question why the pitch is utilized so heavily against LHH when the Fastball is clearly less effective in that platoon matchup.
Slider:
As shown by the tables above, Díaz throws his Slider more often to right-handed hitters than left-handed hitters. Similar to his Four-Seam Fastball, Díaz is below-average at locating this pitch in the strike zone, however he is above-average at getting batters to chase this pitch out of the zone. Díaz was able to generate above-average Whiffs in the strike zone against RHH, however against LHH, Díaz’s Slider was primarily effective at generating ground balls, producing a 50.0% ground ball rate last season, well above league-average. In my opinion, this can be attributed to the difference in where Díaz locates his Slider depending on the batter’s handedness. Against RHH, he primarily locates his Slider low and away, an ideal location to generate a high amount of Whiff; while against LHH, he primarily uses his Slider as a “backdoor” pitch, which can generate both called strikes and weak contact.
Given the fact that Díaz is able to generate so many ground balls with his Slider against left-handed hitters, and because his Fastball performs better against RHH than LHH, I would recommend that Díaz utilize his Slider more frequently against LHH during this upcoming season. In addition, while I do believe he can remain successful with just a two-pitch mix, developing a Changeup might be a good pitch for Díaz to add to his arsenal in the future. With an added Changeup, Díaz will be able to utilize a breaking pitch with arm-side movement that would ideally be able to generate more ground balls and possibly more Whiffs to LHH.
Conclusions:
With further development to his pitch arsenal, Alexis Díaz has the potential to earn quite a few saves for the Cincinnati Reds this season, and could be an attractive trade target for contending teams at the trade deadline. While Díaz has exhibited some command/walk issues, he generates enough Whiffs and ground balls that he should have no problem remaining as the Closer for a rebuilding team such as the Cincinnati Reds next season. With a good first half, and especially if he can limit the amount of walks he allows, I can envision Alexis Díaz becoming a trade target for contending teams at the trade deadline. One potential suitor could be the Philadelphia Phillies, who have had a recent track record of acquiring relief pitchers with high strikeout rates and command issues, such as José Alvarado and Gregory Soto. In conclusion, Alexís Diaz is one of the more underrated relief pitchers in Major League Baseball in my opinion, and his further development and progression will be of interest to me throughout this upcoming season.
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