PHOENIX -- With the first workout for pitchers and catchers less than a week away, the D-backs' front office is still working on possible roster additions. But even so, it's never too early to take a stab at what the team's 25-man roster might look like come Opening Day.
Catchers (3): The D-backs used a three-man rotation last year, and figure to do so again this year, because of Chris Herrmann's ability to play all three outfield positions, as well as the corners in the infield, which gives them depth. Jeff Mathis, who caught Zack Greinke last year, and the recently signed Alex Avila, likely also have spots. Don't completely rule out John Ryan Murphy, however, as he too can play several positions and could give Herrmann a battle.
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First base (1): Every spring it seems there is talk about Paul Goldschmidt getting more days off during the coming season. But when push comes to shove, it's tough to take his bat out of the lineup, and he will certainly never ask for a day off. Last year, he started 152 games, and that's including the five games he missed with a sore elbow in September, so a true backup first baseman is not needed.

Second base/shortstop (5): This is where things will get interesting this spring as the D-backs have a plethora of middle infielders to choose from. If he's healthy, the team could start Nick Ahmed at short and either Brandon Drury or Ketel Marte at second base. Judging by manager Torey Lovullo's comments this winter, it looks like Chris Owings will see time all over the diamond, including some games up the middle. Daniel Descalso is also going to be here and see time backing up second, short, third, left field and possibly even first base.
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Third base (1):Jake Lamb is coming off an All-Star season so his presence is a given. One thing he has struggled with is hitting left-handers (.144/.269/.288 last year), so it's possible that someone like Drury or Owings could get some starts against southpaws this year.
Outfield (3): This is one area the D-backs are still looking to shore up. David Peralta will start in one of the corners and A.J. Pollock will get the nod in center. For now, it seems like Yasmany Tomas will be the other starter, though Lovullo made it clear that Tomas would have to earn his playing time. As far as other options currently on the 40-man roster, there is only Socrates Brito and Jeremy Hazelbaker. If the D-backs do not move one of their middle infielders, it's possible they will have to use some combination of Owings, Descalso and Herrmann as backups in the outfield.

Starting rotation (5): This is probably the easiest to predict right now with returners Greinke, Robbie Ray, Patrick Corbin, Taijuan Walker and Zack Godley all set for spots.

Bullpen (7): The back end of the bullpen should consist of Yoshihisa Hirano, Archie Bradley and Brad Boxberger. Randall Delgado will have a spot if his elbow is healthy, and lefty Andrew Chafin certainly seems to have a spot as well. That will leave a huge battle for the final two spots in the bullpen. The D-backs invited veterans Antonio Bastardo, Michael Blazek, Neftali Feliz, Kris Medlen and Noel Salas to camp, and they join lefty T.J. McFarland and righties Jake Barrett and Jimmie Sherfy among those in the mix. Based on their performances last year, we'll go with McFarland and Sherfy, but these final two spots could wind up providing the biggest surprises of camp.