Projecting the Diamondbacks' Starting Rotation Order

The opening day matchup will feature Gallen, who is likely to be opposed by Dodgers ace Yoshinobu Yamamoto, pending the outcome and usage from the World Baseball Classic.

The second game of the season will almost certainly feature Brandon Pfaadt, who has been following Gallen this spring, pitching one game behind the veteran.

Game three will be one of either Ryne Nelson or Eduardo Rodriguez, but most likely Nelson. Nelson has been following Pfaadt in the rotation order by one day and last pitched on March 11. His next Spring Training start is likely to be March 16.

Rodriguez is still participating in the WBC, having just pitched on March 11 as well. He would not pitch again in the WBC unless Venezuela reaches the final.

If Venezuela is able to advance to the WBC final then Rodriguez would likely pitch on March 17. If Venezuela is knocked out before then, Rodriguez will return to the Diamondbacks' camp and either pitch in a minor league game on a back field, or wait until the 18th for his next start.

It seems most likely that Rodriguez will start in game four of the regular season against the Detroit Tigers at home, but the team has the option to switch things up if they so desire.

That brings us to the fifth game of the season on March 31. Merrill Kelly is making his first Cactus League start on March 13, and would only have enough time to get ramped up to three innings or four at most prior to the fifth game of the season.

Michael Soroka, meanwhile, is also scheduled to pitch on March 13 for Canada in the WBC. He lines up to be able to take that March 31 start as well.

The D-backs will likely face two choices. The first is to start Soroka on March 31 and place Kelly on the injured list, backdated to March 23. He would be eligible to come the IL on April 7.

The other option is to let Kelly make the March 31 start, albeit with just a four-to-five inning target, and utilize Soroka in long relief in a "piggy-back" scenario. Being able to do that would be contingent on not needing to use Soroka in relief in any of the prior four games.

In summary, it is our belief that Kelly will start the year on the injured list, and the rotation order the first time through will be Gallen-Pfaadt-Nelson-Rodriguez-Soroka.

Performance Projections for the Starting Rotation

Regardless of the order, the Diamondbacks are going to need at least one or two of these starting pitchers to outperform their projections. According to FanGraphs' Depth Chart projections, only Kelly is projected to have a sub-4.00 ERA, and that number comes in at 3.94.

Beyond these six pitchers, Corbin Burnes is not expected to return from Tommy John Surgery before the All-Star break.

Minor league starters Mitch Bratt and Kohl Drake are considered to be next up on the depth chart should there be further injuries or underperformance necessitating a call-up. Neither of them have pitched particularly well in Spring Training, however.

Cristian Mena, originally thought to have a leg up as the sixth or seventh starter, was shut down with a recurrence of his Teres Major shoulder strain and is unlikely to be an option any time soon.