Ryne Nelson Wins Competition For Final Rotation Spot

Earlier today, Jack Sommers gave an update on the position player battles, with Kyle Lewis slugging his way onto the roster. Another compelling battle for the final spot in the Opening Day rotation. According to Steve Gilbert, the winner of this competition is Ryne Nelson and Drey Jameson will open the season in the bullpen.

Ryne Nelson will be the @Dbacks 5th starter. Drey Jameson will open the year in the bullpen.
— Steve Gilbert (@SteveGilbertMLB) March 26, 2023

Both pitchers made their respective debuts last September, with Nelson making three starts and Jameson getting four. Both pitchers posted solid run prevention numbers, with ERAs of 1.47 and 1.48 respectively.

However advanced run prevention metrics had mixed opinions on the two pitchers. FIP, xFIP, and SIERA are a bigger fan of Jameson's overall body of work due to a better strikeout rate Statcast's xStats, which takes into account batted ball data, love Nelson's work with a 2.24 xERA compared to Jameson's 4.49. Much of the difference likely came down to fastball results, in which Nelson's 4-seamer had a .234 xwOBA allowed while Jameson's two fastballs had a .333 xwOBA. Considering how fastball-heavy both pitchers are, at 69.6% and 62.3%, it could have tipped the decision in Nelson's favor.

In the interim, Jameson will serve as the long man since he's stretched out as a starter. Given that Arizona will be opening the season with a grueling 10-game stretch against the Padres and Dodgers, additional length in the bullpen is going to be very helpful. Nick Piecoro points out there is a possibility that Jameson could end up converting to short relief, not too dissimilar to Archie Bradley in 2017. Bradley began 2017 as a long man, but eventually ended up being their go-to guy in high leverage situations before the ninth inning by the end of the season.

They could get into a situation where Jameson emerges as one of their better short relief options, a chance they’re willing to take. They could also end up sending him back down at some point early in the season to stay stretched out as starting depth.
— Nick Piecoro (@nickpiecoro) March 26, 2023

It's important for the organization keep Jameson in a consistent role throughout the season and not yo-yo him between starting and relieving. That approach backfired when they tried it with Randall Delgado and Jon Duplantier, leading to both players suffering injuries. Whether that's in the backend of the bullpen or the starting rotation, that's where they'll need to commit to keeping him in the long term.

With Jameson set to start the season in the bullpen, the final spot could come down to Ryan Hendrix and Carlos Vargas.