5 offseason questions looming for D-backs

PHOENIX -- The D-backs had planned to still be playing this week, but a disappointing finish got them started on the offseason early.
As the front office continues its end-of-the-year meetings, here are five questions the D-backs have to answer this offseason.
1. What went wrong in September?
While most of the questions will focus on the future, the D-backs initially have to glance in the rearview mirror and figure out what caused their September swoon.
It's easy to point a finger at the bullpen, but the answer is likely to be more nuanced than that, and involves other aspects of the team, like the offense and collective mindset. Essentially, the D-backs have to determine whether September was more of an outlier or if the months they spent in first place were not a true barometer of the kind of team they have.
The answer they come up with will help them answer the next question.
2. Do they go for it again in 2019 or look to rebuild?
The D-backs will likely lose left-hander Patrick Corbin and outfielder A.J. Pollock to free agency, but they still have one more year of perennial MVP candidate Paul Goldschmidt.
If the front office still believes in the current core of players, then it would make sense to try to add a free agent or two, or make trades that help set them up to take another run at the postseason in 2019.
If they don't believe the team's core is good enough, then the question becomes: Do they do a full-on rebuild, or instead take a small step back?
3. What do they do with Goldschmidt?
The D-backs will certainly pick up his option for 2019, but the big question is whether they look to trade him this winter, extend him, or let him play out his walk year and see what happens after that.
If they're planning on making a run for the postseason, then keeping Goldschmidt is a no-brainer. Even if they are doing a partial rebuild, it likely makes more sense to keep him. However, if they're doing a complete tear down, then maybe they could look to deal him for prospects to help speed up the rebuilding process.
4. How do they replace Corbin and Pollock?
Assuming both leave through free agency, the D-backs have some big holes to fill in the rotation and in center field.
There are some internal candidates, of course, for both spots. Outfielder Jarrod Dyson is under contract for 2019, Socrates Brito has shown flashes of his talent and Jon Jay, who will be a free agent, is a favorite of manager Torey Lovullo.
As for the pitching staff, the D-backs have younger pitchers like Matt Koch, Taylor Widener, Matt Andriese and Taylor Clarke among those who could get a look.
If they want to compete for the postseason, however, the D-backs would likely need to look outside the organization.
5. How to fill out the rest of the roster?
Veterans like infielder Daniel Descalso and catcher Jeff Mathis -- who will both be free agents -- have filled important leadership roles in the clubhouse while also contributing on the field. Even in a rebuild they would bring needed veteran presence.
Improving the bench also should be a priority as the D-backs' insistence on carrying three catchers limited their options.