I'll just get this out of the way: it might be time to end the Ryne Nelson Experiment. At least, for a little while.
When Ryne Nelson first made his debut in 2022, it looked like the D-backs had something special in the young right-hander. His first two major league starts were 6+ inning scoreless outings. He was touched up a bit for 3 ER over 5.1 innings against the Padres but looked very solid in his first small sample at the end of a rough 2022 pitching rotation.
The 2023 season has been a completely different story for Ryne. It took 8 starts before Nelson finally managed a scoreless outing, allowing fewer than three runs only once in that time period. Nelson's ERA has skyrocketed to a dismal 5.53 on the season with a WHIP close to 1.5. In 26 starts in 2023, Nelson has only made it through the 7th inning three times, while also frequently failing to complete even 5 or 6 innings.
He's been batted around for five or more runs nine times so far this season, recording a loss in eight starts. When Nelson took a win in a 5.2-inning, one-run performance against Chicago on September 7th, he recorded his first win since July 19th against Atlanta, before being lit up for six earned runs and a loss in his subsequent start against the Mets.
It was an encouraging sign for this starting rotation when it was announced that the D-backs had optioned Nelson back to AAA Reno on August 13th, following abysmal performances in three of his previous four starts.
With newly recalled RHP Slade Cecconi looking promising, some mild success in bullpen games, and RHP Zach Davies having multiple solid starts after being activated from the IL, it looked like the Diamondbacks' needs to stay alive in the playoff race surpassed their patience for a young pitcher that failed to show steady development of any kind.
However, after an extremely rough six-run outing against Baltimore, Cecconi was eventually sent back down to Reno, and Ryne Nelson was called back up in his place. Cecconi had an ERA of 2.57 over five starts before his blowup start got him sent back to AAA.
With so much riding on every aspect of the game in the coming weeks, the D-backs cannot continuously put the ball in the hands of one who shows zero progress, even after a minor league stint. Ryne Nelson, despite a few quality starts scattered throughout the season, has shown nothing to prove he has the potential to be a quality starter.
Nelson struggles heavily with putting batters away. He regularly fails to deliver the knockout punch on two-strike counts, and while walks and control haven't been his major issue, he generates no swing-and-miss and relies heavily on a predictable fastball.
According to Statcast, Nelson ranks in the bottom 10 in whiffs and strikeouts and sits in the 14th percentile of chase rate. Looking at his Savant page, the bubbles are essentially all blue. The only thing he does well is avoid walks, however with the caveat that most of those ABs still turn into base hits.
Pitching Coach Brent Strom talked about Nelson potentially tipping pitches, and although committing to getting it figured out, neither Strom nor Nelson seemed to have any answers as to what was going wrong for the young arm.
Nelson's frustration showed in his interview, which is understandable, but you never want to hear your pitchers--young or not--be at a loss with regard to what could be causing blowup starts over and over.
The D-backs currently hold the 2nd Wild Card spot. So now is not the time to throw a struggling young pitcher out repeatedly in hopes that he figures it out.
While Reno pitchers Bryce Jarvis and Slade Cecconi are still unproven and haven't been without struggle, there is no reason to believe they would do more damage to the season than Ryne Nelson already has.
This is not to argue that Nelson is totally lost, or can never improve. And granted, Arizona's hands are tied when it comes to their thin starting rotation--the main reason Nelson and Davies have had such long leashes. But it should be time to look at other options. In the middle of an intense playoff push, you can't be throwing a 20-sided die hoping for it to land on QS.
Don't get me wrong, I could also write an entire piece on Zach Davies' continued struggles despite multiple chances. But we at least know what Davies can do. It's time to stop wondering about Nelson and give him some serious time to change his approach. It's unlikely the team would be worse off without him, for now.
Whether or not he will improve as time goes on, Ryne Nelson is clearly not ready for this, and the D-backs are wrong to continue giving him chances over some of the other talent that's been showcased by their young pitching staff.