As we finish off this season, players are looking to establish themselves and make statements entering 2027. That is especially true on the mound, where there are only a few guys who have locked down spots for next season. One pitcher who has impressed in his late season audition is Riley Cornelio and I wanted to talk about him a little bit.
Cornelio has had a few different opportunities at points this season. In total, he has thrown 27.2 innings across 14 outings. Cornelio initially got called up
in late April, but his only extended runs have been in July and now down the stretch in September. Early in his big league career, Cornelio looked a bit overwhelmed, but that is starting to change as he gets more experienced.
Riley Cornelio’s go-to pitch is his slider. It is a true bullet slider that looks like a fastball before dropping off the table. Everything about Cornelio’s arsenal is built around getting to that slider. When Cornelio can execute his slider, it is game over for hitters. We saw that in his excellent opener appearance yesterday.
When you look at the data on Cornelio’s slider, the numbers are pretty ludicrous. The pitch generates an insane 53.2% whiff rate. Among pitches thrown at least 200 times, Cornelio’s slider has the 4th highest whiff rate of any offering in baseball. Mason Miller’s slider, Adrian Morejon’s changeup and Erik Miller’s slider are the only pitches that generate empty swings at a higher rate.
That pitch is Cornelio’s crown jewel. He has always had a nasty slider in his bag. The key is making everything else work too. For most of this season, control has been a big issue for him. Cornelio’s 17.7% walk rate is a big reason why he has a 4.88 ERA despite having a premier swing and miss offering. He also allows a fair share of hard contact.
It is worth noting that Cornelio’s command has looked noticeably better since he was last re-called in early September. We only have a 3 outing sample, but Cornelio has only walked 2 hitters in 7.2 innings this month. Honestly, I think his 17.7% walk rate is a bit of an outlier.
Throughout Cornelio’s career, his walk rate has consistentlybeen between 10 to 11%. That is not amazing by any means, but if he can replicate that in the big leagues, he will be effective. I also think there is one recent tweak he made that will make throwing strikes a bit easier.
For most of his career, Cornelio has been a two-pitch guy. His fastball and slider are both good pitches, with the latter being fantastic. However, it is tough to survive in today’s game with just two pitches. That is especially true given that Cornelio’s slider is more of a chase pitch.
Midway through this season, he added a cutter. We saw glimpses of the pitch at times, but he has fully unleashed it in September. This year, Cornelio has thrown his cutter 8.5% of the time. However, in September that number spiked to 23.9%. The pitch is used to bridge the gap between his fastball and slider, which is working wonderfully.
That third shape makes the hitter’s decision much more difficult. The 90 MPH cutter sits right between his 85 MPH slider and 96-97 MPH fastball both in velocity and movement. It is a really good addition to his arsenal and I think it could take him to the next level.
I think Cornelio now has the arsenal to thrive as a 1 inning or multi-inning reliever. He looks really comfortable as a 2 to 3 inning opener, so that could be a home for him. However, with a whiff rate of 35.5% this season, I would like to see what he could do in late innings next year.
The ability to generate whiffs is the highlight of Cornelio’s game and he truly does it at an elite level. In his last 300 pitches, Cornelio has generated 56 whiffs, one of the best marks in all of baseball. For context, Cade Cavalli is right behind him at 55 whiffs.
As you can see, I am bullish on Cornelio, but he is far from a finished product. The command will need to be better for him in 2027. Issuing 22 walks in 27.2 innings is just not good enough. Given his history of mediocre but not awful command, there is some hope on that front though.
When Cornelio first came up, he felt overwhelmed by the moment at times. There were moments where his mound presence was shaky. If he wants to be a late inning arm, that cannot happen. To his credit, Cornelio has gotten a lot better at that and looks like a much more confident pitcher.
Riley Cornelio’s surface level numbers do not jump off the page, but I think he is a sneaky breakout candidate. What he has been doing in his last few outings is highly encouraging. In his last 7 outings, Cornelio has a 2.77 ERA. With his filthy slider, new cutter and hard fastball, Cornelio has what it takes to be a quality big league arm.
A lot of the guys who have been put in the Nats bullpen just do not have the necessary talent. I do not think talent is a problem for Cornelio. For him, it comes down to three C’s. The three C’s are command, confidence and cutter. All three of those things could lead him to a big year next season.
