Ryne Nelson has all the tools to be an effective big league starter

Nelson has the combination of size, quality stuff, and poise to be an effective big league starter for the Diamondbacks.

© Rob Schumacher/The Republic / USA TODAY NETWORK

Ryne Nelson's first two big league starts have been nothing short of impressive. Facing the top two teams in the National League West, Nelson has pitched 13 scoreless innings with 13 strikeouts vs. 1 non-intentional walk and allowed just 6 hits. Those 13 scoreless innings are a Diamondbacks franchise record for consecutive scoreless innings to start a career by a starting pitcher.

The 24-year-old right-hander was a 2nd round selection and the 5th player selected by Arizona in 2019 out of the University of Oregon. He was unable to settle into a consistent role in college, moving between the rotation and the bullpen. Despite his inconsistent track record, his stuff and potential upside as a starter made him an appealing prospect that could develop into a big league starter if his development went well.

Three years later, we're seeing the faith that Arizona put in Nelson come to fruition. After missing out on a potential season in 2020 thanks to COVID wiping out the Minor Leagues, Nelson pitched at High-A and AA in 2021. He started 2022 with Reno, but experienced issues as offseason mechanical changes caused his velocity to dip. In his first 8 starts with Reno, Nelson's average fastball velocity was above 93 MPH only once. The player development staff was able to fix that, with Nelson averaging 93+ in 15 of his last 18 starts with the Aces. 

In his first two big league starts Nelson has relied heavily on his 4-seam fastball, throwing the pitch nearly two out of every 3 pitches. In both starts, the pitch averaged 95 MPH and a spin rate of 2226 revolutions per minute (RPM). While the pitch has a below-average total spin rate compared to other MLB pitchers, ranking in the 45th percentile according to Statcast, it has an active spin rate of 98%. As a result, the pitch does a great job of staying almost purely vertical in its movement profile.

The question to ask is why is all that information important? The answer is a vertical fastball movement profile is much more effective at getting swings and misses up in the zone, where you're more likely to run into swing paths nearly parallel to the ground. Nelson's 4-seamer has 3.3 less inches of vertical drop than the average MLB 4-seamer, which means it has 3.3 inches of rise from the hitter's perspective. As a result, Nelson has already generated 20 whiffs in 2 starts on the pitch.

While the fastball is the main pitch of his arsenal, Nelson also features some solid secondary offerings to keep batters guessing. His curveball has a 12-6 shape, which means it breaks straight down, and he mostly uses it to steal strikes early in the count. There is enough movement that it has potential to be a put-away pitch to go with the 4-seamer if he wants to aim for the knees and below. 

The slider is Nelson's best secondary pitch, generating 4.3 extra inches of horizontal break and 1.7 inches of vertical break compared to the average slider. That is his main put-away pitch against right-handed hitters, when he's spotting it down and away from the hitter. It will be interesting to see how he incorporates that pitch against left-handed hitters, whether it's to land strikes on the back door or get swings and misses aiming for the backfoot. 

Nelson's changeup is a distant third pitch that will still need some refinement to be a staple in his arsenal. The pitch doesn't get as much drop compared to the average change-up due to a higher spin rate. The pitch gets close to average horizontal movement, something critical when trying to locate down in the strike zone and avoid a more vertical swing path from the hitter. Against left-handed hitters, Nelson uses his changeup as his main offspeed pitch while he prefers the slider against right-handed hitters.

When going right, Nelson can command the full arsenal of pitches against any opposing lineup. The biggest limiting factor will his stamina in starts and maintaining the high velocity in his starts. In his two starts, Nelson has experienced a smaller fastball velocity drop around 50 pitches before a bigger one around 75 pitches. It's not something to be overly concerned about as he finishes the season, but something to watch for next year.

The question about his long term projection will be his ability to hold up under a 160-inning workload. So far, he's shown the ability to handle the workload and stay healthy. He'll have the chance to earn a rotation spot, if he's not on the inside track for it, next spring with the hope he'll add some youth and stability to a starting rotation that desperately needs it.