Arizona Diamondbacks’ pitching depth: the 40-man roster candidates

Arizona’s Opening Day rotation of Zack Greinke, Robbie Ray, Zack Godley, Taijuan Walker and Patrick Corbin, has the potential to be as good as any in the National League this year. but as we discussed last week, the 2018 Diamondbacks are all but guaranteed to need starters beyond them. On historical average, they’ll have to find 44 replacement starts, probably beginning before the end of April. Let’s look at the pitchers who could help provide those, beginning with the men currently on the 40-man roster or the 60-day disabled list.

Archie Bradley

• Career as starter: 34 GS, 10-12, 5.18 ERA
• Most recent starter season: 2016 - 26 GS, 8-9, 5.02 ERA

There’s little doubt that, all being well, Bradley will operate out of the D-backs’ bullpen as a versatile and flexible reliever, capable of giving the team multiple innings when needed. But if the need arises? Bradley has made no secret of still preferring to be a starter: “I definitely love starting and want to do that again [after] understanding and learning some of the things I learned this year... That’s obviously what I would prefer to do; I think I could be a really good guy every fifth day.” And Torey Lovullo has said Archie would be one potential option, stating, “There’s a thought that if something goes wrong with one of our five starters, he would be close enough to stretch him out that way, and possibly use him.”

Randall Delgado

• Career as starter: 53 GS, 11-20, 4.17 ERA
• Most recent starter season: 2017 - 5 GS, 0-1, 2.52 ERA

Behind Godley, Delgado was the team’s most used spot-starter last year, and the results weren’t bad. Randall posted an impressive K:BB ratio of 24:5 over five starts, allowing more than a single earned run just once. His main problem was length: he never completed six innings, and his pitch count topped out at 93. But at least for now, he’s more likely problem than solution. Delgado still has not appeared in the Cactus League and was shutdown after a bullpen session over the weekend triggered some push back from his troublesome left oblique. While he said on Monday he feels better, he will need to prove himself healthy enough to work out of the bullpen, before even becoming part of the conversation.

Matt Koch

• Career as starter: 2 GS, 0-0, 2.45 ERA
• Most recent starter season: 2016 - 2 GS, 0-0, 2.45 ERA

After an impressive cup of coffee in 2016, Koch managed the uncommon infinite ERA in 2017, being charged with three earned runs and failing to retire a batter in his only appearance, out of the bullpen. Shoulder issues all but wiped out the first half of his minor-league season, limiting him to 12 minor-league starts. That included an ugly one with a Game Score of -13 (yes, negative thirteen), which helped lead to an 8.40 ERA with the Aces. He has looked a lot better this spring, allowing two earned runs over 8.1 innings. The fact he has been almost exclusively a starter over the last couple of seasons might give him an advantage over the converted relievers above.

Shelby Miller

• Career as starter: 120 GS, 36-49, 3.69 ERA
• Most recent starter season: 2017 - 4 GS, 2-2, 4.09 ERA

It’d be nice if we could keep the rotation together until Miller is able to return, and by coincidence, today brought us the above. It’s taken from Miller’s first bullpen session as he makes his way back from Tommy John surgery (though his golf swing already looks pretty good...). There’s still no clear timetable for his return: if he follows the same timetable as Patrick Corbin, early August would be about right, but that might be on the conservative side, with Miller reportedly feeling very good. However, Shelby may not be 100% effective out of the gate: he won’t have faced major-league hitters for 16 months or so, and I’m inclined to view any production from him this year as a bonus, rather than anything.

Albert Suarez

• Career as starter: 12 GS, 1-4, 4.28 ERA
• Most recent starter season: 2017 - 12 GS, 1-4, 4.28 ERA

Having just discussed Suarez earlier today, in our out of options piece, I’m tempted just to copy-paste that paragraph. As explained, this Rule 5 pick needs to stay on the roster (or DL) somewhere for the entirety of this year, or be offered back to the Giants. If Delgado isn’t ready, that would be the most likely role for Suarez on Opening Day. But if the team then needs a starter before Randall returns, this could provide another way by which he could stick around. It is potentially an issue that his only appearance of longer than three innings last year, in the majors or minors, came in the Venezuelan winter league, pitching for Leones del Caracas. So his stretching out might take longer than most.