Arizona Diamondbacks Too-Early Opening Day Roster Projection

The Arizona Diamondbacks will officially open spring camp on February 12 when pitchers and catchers report. In truth, many players have been at the Salt River Fields facility for weeks already, working out and getting ready.
The D-backs' off-season is not yet complete, as they have the stated goal of adding a reliever, preferably one with closing, high-leverage experience, They also would like to add a right-handed bat to balance out the roster, replacing the Randal Grichuk role.
In lieu of those moves however, here is a breakdown and projection of what the Opening Day roster may look like. Consider this a snapshot in time, based on what the 40-man roster looks like as of this writing.
We'll update this every few weeks between now and opening day. All projections are based on good health, as there are no reports of any injuries at the moment that would keep a player out for opening day.
Catcher
Lock: Gabriel Moreno (R)
Probable: Jose Herrera (S)
Long shots: Adrian Del Castillo (R) and René Pinto (R).
Herrera is considered the better defender and has the most experience working with the pitching staff. He is also out of minor league options.
General Manager Mike Hazen indicated Del Castillo still needs to work on his defense and is likely to start the year back with Triple-A Reno. If he were to make the roster over Herrera, then Herrera would need to be DFA'd.
Pinto, who is also out of options, was picked up this offseason for depth and is also on the 40-man roster. He would only make the roster in a worst-case injury scenario however, and is a likely DFA candidate before the end of spring training.
Infield
Locks: 1B, Josh Naylor (L) 2B Ketel Marte (S) SS Geraldo Perdomo (S) 3B Eugenio Suarez (R)
Probable: Grae Kessinger (R) Blaze Alexander (R)
Long shots: Jordan Lawlar (R) and Tim Tawa (R)
Kessinger was added to the 40-man roster due to his defensive reputation. Torey Lovullo values defense above all else from the utility spot and Kessinger can back up shortstop. He has options however and the team would not lose him if they decided not to place him on the opening day roster.
Alexander's positional flexibility and prior MLB experience gives him a leg up on the other candidates at the moment. It's even been talked about whether to give him outfield reps or not during spring, which is one more opportunity for him to stick.
Lawlar still needs more reps to work on his defense according to Mike Hazen. Tawa was added to the roster to protect him from the Rule-5 draft after a 31 homer season. A breakout spring could mean the utility man replaces Alexander.
Outfield and DH
Locks: LF Lourdes Gurriel Jr. (R), CF Jake McCarthy (L), RF Corbin Carroll (L), DH Pavin Smith (L)
Probable: Alek Thomas (L)
Long Shot: Jorge Barrosa (S) Cristian Pache (R)
Pavin Smith should be on the opening day roster, but may not be in the opening day lineup as the D-backs are expected to face lefty Justin Steele when they meet the Cubs in the season opener. Smith is out of options and is certain to get a chance to follow up his second half breakout last year.
Alek Thomas is highly likely to beat out Jorge Barrosa for the fourth outfielder spot. Cristian Pache is a non-roster invitee who bats right-handed, and is also a long shot fourth outfielder candidate.
Rotation
Locks: Zac Gallen (R), Corbin Burnes (R), Merrill Kelly (R), Eduardo Rodriguez (L)
Probable: Brandon Pfaadt (R)
Longshot: Ryne Nelson (R) Jordan Montgomery (L)
For some it may seem controversial to list Brandon Pfaadt as probable. Pfaadt is widely considered to be a lock for the fifth rotation spot. But it's a fact that Ryne Nelson out-pitched Pfaadt by a fairly wide margin over the final three months of the season.
A poor spring by Pfaadt and and good spring by Nelson could flip the script. Nelson is still considered a long shot for the rotation, but is listed as a lock in the bullpen section however as he is also a reliever candidate.
Pfaadt would almost certainly need to stay stretched out in Triple-A if he were demoted from the rotation.
Jordan Montgomery meanwhile is likely to be traded before the end of spring training. If he's not, he'll almost certainly get another chance to start, which is one more reason why Pfaadt is listed as probable instead of a lock.
Bullpen
Locks: Justin Martinez (R), Kevin Ginkel (R), Ryan Thompson (R), Ryne Nelson (R), A.J. Puk (L), Joe Mantiply (L)
Probable: Seth Martinez (R), Kyle Nelson (L)
Long Shots: Drey Jameson (R), Bryce Jarvis (R), Jose Castillo (L), Josh Winder (R)
As this is a roster article, I don't attempt to answer the question of who will close if the D-back fail to acquire a new closer in the next couple of weeks.
Seth Martinez was picked up off waivers from the Astros and is listed as probable due to the fact he is out of minor league options. If he doesn't make the club he'll be DFA'd. Kyle Nelson is listed over Drey Jameson and Bryce Jarvis as the team may want a third lefty in the pen with four of five starters likely to be right-handed.
Jose Castillo and Josh Winder are non roster invitees signed to minor league contract. If they are outstanding and impress in spring, the team may look to make room for them, but it's unlikely.
Summary
There are nine position players, four starters, and six relievers that are locks for the opening day roster, for a total of 19.
Surprisingly, that leaves seven opening day roster spots up for grabs, four position players, one starter, and two relievers.
As mentioned at the outset, this could change radically if the team is able to complete their offseason goals of getting a closer and a right-handed slugger (or just bring Randal Grichuk back).
Finally, remember that over the course of a season, the team will use upwards of 45 to 50 players before it's all said and done. The opening day roster is the beginning, not the end.