With a combination of the off-days on the schedule, and the imminent(ish, with a large side order of hopefully) return of Taijuan Walker, the Diamondbacks may not need a fifth starter for a while. Michael already discussed whether perhaps Patrick Corbin might be dropped from the rotation, but it could be that Delgado ends up being the odd-man out. We'll probably know more after it is figured out who will be starting the series (and road-trip) finale in Miami tomorrow afternoon. That might then give us a clue as the rotation going forward.
Certainly, there's no doubt that Delgado has stepped up admirably, in much the same, largely unexpected way as Zack Godley. There was a point where Delgado's roster spot seemed seriously in doubt: On April 23, his ERA was above eight, mostly due to the long-ball, having allowed four home-runs in only 12.1 innings of work. The switch seems to have clicked in the marathon 2-0 win over the Rockies at Chase Field, where he threw three shutout innings and got the win. Since April 23, Randall has thrown 24 innings with an ERA of just 1.13, with a K:BB ratio of 28:4 and just the one home-run allowed. Maybe he could teach Corbin about keeping the ball in the park?
He got a save in his last bullpen outing, making him the 15th pitcher in D-backs history to both start and get a save in the same season. Having already done that in 2015, he joins Corbin (2012 + 2016) and Josh Collmenter (2014 + 2015) as the players with multiple such seasons on their resume for Arizona. Although most of those have got just a "1" in their column for saves or starts. The only pitchers with multiple saves and starts in the same year for the D-backs are Mike Morgan (five Sv, four GS in 2000) and Elmer Dessens (two Sv, nine GS in 2004). Delgado has the starts to join them; we'll see whether the rest of the season has any more saves!