With Spring Training fast approaching, MLB.com takes a look at a different aspect of this year's D-backs squad each day this week. Today's topic: Predicting the 25-man roster.
PHOENIX -- Predicting an Opening Day roster halfway through Spring Training is challenging enough. Trying to come up with one before pitchers and catchers even report? Nearly impossible.
With that being said, here's an early look at what the D-backs' 25-man roster could look like on Opening Day. We'll continue to do these periodically throughout Spring Training and see how they change.

Catchers:Jeff Mathis, Chris Herrmann, Chris Iannetta
The D-backs will likely carry three catchers because of Herrmann's versatility -- he can play left and right field, as well as in the infield.
First base:Paul Goldschmidt
Enough said.
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Second base:Brandon Drury
Sounds like the D-backs would like to give Drury every opportunity to win the starting job at second base. Don't rule out Ketel Marte, Chris Owings and Daniel Descalso, though.
Shortstop:Nick Ahmed
Expect a lot of competition here with Marte, with Owings also likely getting a look. The D-backs may end up giving Ahmed the nod because of his defense.
Third base:Jake Lamb
Lamb will get the bulk of the starts at the hot corner, and he will likely get more at-bats this season against left-handed pitching, unless he shows he shouldn't.

Utility infield: Descalso, Owings
Both are versatile and can play second, short and third, giving first-year manager Torey Lovullo lots of options.
Outfield:Yasmany Tomas, A.J. Pollock and David Peralta
Owings is a possibility to see time at all three of the outfield positions, particularly the corners.

Backup outfielder:Gregor Blanco
Assuming the D-backs carry 12 pitchers, three catchers and three backup infielders, that leaves room for just one backup outfielder, but Owings can play all three outfield spots and Herrmann can play the corners. Blanco might be the early front-runner, but also keep an eye on Socrates Brito and Jeremy Hazelbaker.
Starting pitchers:Zack Greinke, Shelby Miller, Robbie Ray, Taijuan Walker, Patrick Corbin and Archie Bradley
Yes, I cheated here and listed six starters, because I can't choose just five of those guys.
Bullpen:Fernando Rodney, Randall Delgado, Jake Barrett, Evan Marshall, Andrew Chafin and Enrique Burgos.
Honestly, this is way too early to even begin to sort out the bullpen. There will be a fierce battle for spots, with Rodney, Delgado and Barrett as the only ones very likely to make it at this point. The D-backs also have some veteran non-roster relievers who could sneak into a spot. There's also a chance one of the starters that doesn't make the rotation will slide to the bullpen, too.