Why Ryne Nelson's Spring Debut Matters for D-backs

The Arizona Diamondbacks are set for their first night game of Cactus League play, taking on the Seattle Mariners in Peoria for a 6:10 p.m. first pitch. This game will be broadcast for free on D-backs.TV.

Right-hander Ryne Nelson will take the mound for the first time in a live game. There's a decent chance D-backs fans will be getting their first look at the team's eventual opening day starter — or at least one of the leading candidates for that honor.

Arizona Diamondbacks' Ryne Nelson Makes First Spring Start

Arizona Diamondbacks right-hander Ryne Nelson (19) pitches against the Los Angeles Dodgers at Chase Field in Phoenix, on Sept. 24, 2025. | Joe Rondone/The Republic / USA TODAY NETWORK via Imagn Images

Nelson had been on a similar schedule to right-hander Merrill Kelly. Kelly will be unable to make his opening day start as a result of intercostal nerve irritation. Though manager Torey Lovullo has been adamant that all alternative options are on the table, Nelson does seem to be one of the frontrunners for the nod at Dodger Stadium.

So while spring results do not matter in terms of final score, or even ERA, Nelson's first real-game action is something to keep an eye on in terms of velocity and command. Nelson is coming off an exceptional run this past season, throwing to a 3.16 ERA in 23 starts after moving back into the rotation.

He won't have to wonder about his role this year. Especially following Kelly's injury, it would likely take a massive underperformance or an injury to force the 28-year-old out of the starting rotation ahead of 2026.

Nelson will go up against Mariners veteran righty Luis Castillo. Castillo did not have his greatest season in 2025, but still posted a sturdy 3.54 ERA over 180.2 innings.

Arizona Diamondbacks Reveal Starting Lineup vs Mariners

The Diamondbacks' lineup for their matchup Friday night is as follows:

1 - CF Jordan Lawlar

2 - 2B Tim Tawa

3 - 1B Pavin Smith

4 - C James McCann

5 - SS Ildemaro Vargas

6 - LF Ryan Waldschmidt

7 - DH A.J. Vukovich

8 - 3B LuJames Groover

9 - RF Kristian Robinson

Arizona's WBC players are beginning to be phased out, with a lineup mostly devoid of "regulars." Jordan Lawlar has been hot to open spring, and has looked at minimum competent in center field. Top prospect Ryan Waldschmidt has seen some success both offensively and defensively.

Meanwhile, Vargas is a name to watch in the backup shortstop battle. The utilityman had some success in a limited role in 2025, and remains a trustworthy veteran for manager Torey Lovullo. He's currently on a minor league deal, and is not a member of a 40-man roster, however.