The Arizona Diamondbacks have a looming decision to make with regard to their starting rotation.

As right-handed veteran Merrill Kelly is set to return from the injured list during Arizona’s upcoming series with the Baltimore Orioles, one of the D-backs’ healthy starting pitchers will be forced out of the rotation — either to a relief role or the minor leagues.

There’s not much danger for Zac Gallen, who has been the D-backs’ ace and opening day starter at times through his years in Arizona. Eduardo Rodriguez has allowed one earned run in three dominant starts.

The decision comes down to the three younger arms: Ryne Nelson, Brandon Pfaadt and Michael Soroka. Nelson and Soroka both have a decent sample size of relief experience in the majors.

“We’re going to figure this whole thing out, we haven’t had the conversation,” manager Torey Lovullo said of the roster crunch to. D-backs.TV’s Jody Jackson on Saturday.

“We need to let all the dust settle, and we have some decisions to make. We have some thing that we need to start discussing very seriously.”

But as tough as it may be to decide between three of pitchers the D-backs clearly believe in, there is a clear option to move out of his current role — Pfaadt. Here’s why:

Why Brandon Pfaadt may be best long relief option