What to expect from Riley Cornelio in his Washington Nationals debut

Q: What are Riley Cornelio's key pitching stats before his MLB debut?

Before his debut, Riley Cornelio recorded 27 strikeouts in 18.1 innings, achieving a strikeout rate of 13.25 K/9 this season.

Q: How did the Nationals utilize Riley Cornelio in his debut?

The Nationals plan to use Riley Cornelio in a bulk relief role, combining his efforts with Miles Mikolas to provide length in the game.

Q: What pitches does Riley Cornelio primarily throw?

Riley Cornelio primarily throws a mid-90s fastball and a sharp slider, with the fastball being used over 60% of the time.

Q: What challenges might Riley Cornelio face in the MLB?

Cornelio may struggle against lineups stacked with left-handed hitters due to his limited pitch arsenal, primarily relying on two pitches.

HARRISBURG, PENNSYLVANIA - JULY 27, 2025: Riley Cornelio #29 of the Harrisburg Senators pitches during an Eastern League game against the Akron RubberDucks at FNB Field on July 27, 2025 in Harrisburg, Pennsylvania. The Senators beat the RubberDucks, 7-0. (Photo by Thom Wood/Diamond Images via Getty Images) | Diamond Images/Getty Images As we all know, the Nationals badly need talented pitchers. After yesterday’s game, they called up one of the more promising arms in their system in Riley Cornelio. The 25 year old was the Nats 7th round pick in 2022 who broke out last season before taking another step this year. Now, he is getting a chance to prove himself in the big leagues. Today, Cornelio will be part of a rotating cast of characters who combine with Miles Mikolas to give the Nats length. This plan worked perfectly last time the Nats utilized it. PJ Poulin opened before Mikolas fired four scoreless innings. After Mikolas left the game, Andrew Alvarez threw 4.1 scoreless innings of his own to secure a shut out for the Nats. The hope is that the Nats can repeat the trick, this time with Cornelio. In my opinion, Cornelio is more talented than Alvarez and has a higher ceiling. He throws harder than Alvarez, sitting in the mid-90’s, while also having a really sharp slider to pair with his heater. Over the last couple of years, Cornelio’s heater has taken massive strides. He added three ticks between 2024 and 2025, and added another tick this offseason. It is not just pure velocity for Cornelio either. He has a unique fastball shape that gets ride and run. This season, he has leaned heavily on his dynamic heater, throwing it over 60% of the time. Before this season, Cornelio was more known for his wipeout slider than his heater. That devastating slider is still there, and it is a massive weapon for him particularly against right handed hitters. He throws the slider 45% of the time to righties, and gets a ton of whiffs. Cornelio has been racking up the strikeouts all season so far. In his four starts, Cornelio 27 strikeouts in 18.1 innings. These kinds of strikeout numbers are new for Cornelio, who had 9.4 K.9 last year. This season he has raised that to 13.25 K/9. The Nats are going to use Cornelio in a bulk relief role to start, but I would be intrigued by him as a higher leverage bullpen arm. He is basically a two pitch guy, only throwing his changeup 6.6% of the time. Having a shallow arsenal causes him to struggle when facing a lineup for a second or third time. I am also not sure how he would fare if teams stacked their lineup with left handed hitters. He is far from a perfect prospect, but Cornelio has good stuff and solid command. The Nats have too many guys on the staff who just do not have dynamic stuff. Cornelio will at least provide that. He can get plenty of whiffs and has two pitches he can lean on. Hopefully Cornelio will stick around for a little while. I understand the logic, but it is frustrating to see guys like Andrew Alvarez and demoted immediately after having good outings. Utilizing optionable arms is smart, but in this bullpen, I want to see more guys who look good. While he is not a mega-prospect, Riley Cornelio is a guy with plenty of helium who has taken massive steps the last couple of seasons. Last year we saw come out of seemingly nowhere, and I think Riley Cornelio can do something similar. Congrats to Riley and I can’t wait to see him pitch in the big leagues.