Ranking the 2019 Arizona Diamondbacks rotation candidates

I’ll be slightly shaking up the system for this area in the second part - the “will be” section. Because there seems little point in asking who are going to be the starting pitchers on the 2019 Arizona Diamondbacks Opening Day roster. Barring poor health, it seems all but certain to be Zack Greinke. Robbie Ray, Zack Godley, Luke Weaver and Merrill Kelly. The questions are more to do with depth, because it’s always worth remembering, we’ll need more starting pitchers than five. The chart below shows the number of starting pitchers used by the D-backs each season, and the number of starts made by those outside the top five most used in that role.

The thin lines indicate the trend, and you can see that both the number of starting pitchers used in a season, and the games required from outside the “frontline 5”, have both been heading slightly upwards in the life of this franchise. From 1998-2018, the average was 9.9 starting pitchers needed, and 28.8 “replacement games”. But over the last five seasons, those numbers are 10.8 starters and 31.4 replacement games. All told, it’s probably reasonable to assume the D-backs will use an additional five men in the rotation, who’ll combine to make 30 or so starts this year. That’s why it’s not just the Opening Day starters who’ll be important.

Arizona did add another potential candidate since we originally discussed the non-roster invitees. Veteran Ricky Nolasco will be in spring training, seeking to make it back to the majors for the first time since 2017, when he went 6-15 with the Angels. This seems a bit of a long shot, as Nolasco hasn’t had an ERA+ better than 94 since 2013, with his overall figure after that point being 82. Still, he’s in the list for ranking below, along with the other non-roster candidates, those on the 40-man roster, and Taijuan Walker, expected back from Tommy John at some point in the season. While the top five may be fairly well established, there are still some interesting topics:

• Who’s #1? Greinke will, one presumes, be the Opening Day starter. But do we consider Ray the “true” staff ace?
• How do you order the back end? Godley, Kelly and Weaver all have upside... yet are also far from being sure things.
• Who should be first on the bus from Reno? It won’t take long - last March, we found typically 30 games - before we need a sixth starter. And in 2018, it only took until game #19.
• Bonus question for the comments: how far down are you satisfied with the depth? Do we have ten credible candidates to start this year?

Link to poll

We’ll have the answers for you on Thursday.