Other potential starters
Ryne Nelson
Ryne Nelson had a 5.31 ERA, 5.07 FIP, and 1.42 WHIP in 144 innings last year. Nelson only walked 7.4% of the batters he faced but had a poor 15.5% strikeout rate, along with a HR/9 of just 1.50. xFIP (5.30), SIERA (5.24), and DRA- (125) all made Nelson a pitcher comparable to Henry. However, Nelson was worse at limiting hard contact with a 90.8 MPH exit velocity, 11.6% barrel rate, and 42.6% hard-hit rate.
Slade Cecconi
Slade Cecconi pitched 27 innings in the big leagues last season, allowing 13 earned runs, only walking four batters, surrendering four home runs, and striking out 20. Cecconi's numbers at Triple-A weren't all that bad. His 6.11 ERA is only slightly worse than the league average in the PCL. But he had a quality 3.28 K:BB ratio, and his 1.86 HR/9 seems somewhat fluky. His HR/FB ratio clocked in at 17.1%.
Blake Walston
Blake Walston was the D-Backs' first-round pick in 2019. The lefty spent all of 2023 at Triple-A Reno, where he owned a decent 4.52 ERA, 5.39 FIP, and 1.57 WHIP through 149.1 innings. Walston's 14% walk rate was abnormally high for him, as he walked just 8.5% of opponents faced in 2022. However, some of this could be chalked up to struggling to adjust to the new automated ball-strike system. His 15.4% strikeout rate was also significantly worse than in 2022, but his 0.53 HR/9 rate was outstanding. Walston was added to the team's 40-man roster to protect him from the Rule 5 draft.
Corbin Martin
Corbin Martin was originally acquired in the Zack Greinke deal in 2019. But he's only pitched 57.2 innings in the big leagues since debuting in '19. Martin did not pitch in 2023, as he underwent tendon surgery in March 2023, causing him to miss the entirety of the campaign. How he'll look after coming off major surgery is unknown, but Martin could play into the team's depth, at the very least.