PHOENIX -- The D-backs surprised most of baseball this year, going 93-69 -- a complete 180 from 2016 -- and qualified for the postseason for the first time since '11. But for general manager Mike Hazen and his staff, the challenge to repeat that in '18 will make this offseason an interesting one.
Hazen will continue to balance the desire to maximize the team's current window to contend with the desire to have sustainable success going forward.
• D-backs progressed, surprised everyone in '17
After winning the National League West in 2007 and '11, the team took an all-in approach and wound up bottoming out a few years later. That's something it is looking to avoid this time around.
With that in mind, here's the offseason outlook for the D-backs:
Biggest needs
1. Bullpen: With Fernando Rodney a free agent, the D-backs will need a closer in 2018. The right-hander has expressed interest in returning, and despite a poor ERA, he pitched well for the most part in that role. If the team does not decide to bring Rodney back, setup man Archie Bradley is an obvious internal candidate to replace him. Keep in mind that the D-backs built a good portion of their successful pen in '17 with veteran guys who were coming off down years, including T.J. McFarland, J.J. Hoover and Jorge De La Rosa. Look for them to offer non-roster invitee contracts to add bullpen depth.
Possible free-agent fits: Rodney.

2. Catcher:Jeff Mathis will enter the second year of a two-year deal, so he's a lock here. The question is who will join him. Chris Iannetta, who provided some pop at the position for the D-backs in 2017, is a free agent. He fit in well in the clubhouse, and they may look to bring him back. Chris Herrmann's versatility makes him attractive, but he is arbitration-eligible and really struggled at the plate this year. The team prioritizes defense at this position, so it will be interesting to see what it does.
Possible free-agent fits: Iannetta, Jonathan Lucroy.

Gray areas
1. Replacing/re-signing J.D. Martinez: The acquisition of Martinez in mid-July was a stroke of genius by Hazen and his staff. Martinez quickly assimilated into the D-backs' clubhouse and became a leader both on and off the field. Martinez, though, is now a free agent, and while he has expressed a desire to remain in Arizona and the D-backs have said they'd like to keep him, finding a way to make it work within their payroll seems problematic. If they don't keep him, they will likely rely on a return to health by Yasmany Tomas to fill Martinez's spot in the lineup.

2. Who's at short?Chris Owings won the starting shortstop job over Nick Ahmed and Ketel Marte in Spring Training this year. Injuries to Owings and Ahmed, however, thrust Marte into the starting role, and he excelled. With both Owings and Ahmed expected to be at full strength next spring, the team has to decide whether to once again have a three-way competition, or deal one of them during the offseason. Marte is under club control next year, while Ahmed is eligible for salary arbitration this offseason for the first time and Owings for the second time.

3. Who to keep? Speaking of salary arbitration, the D-backs have a whopping 14 who are eligible this offseason. Based on arbitration projections by MLBtraderumors.com, those 14 players could wind up costing Arizona $52 million. The team will have to decide whether it wants to non-tender some of them -- like Herrmann, Shelby Miller or Hoover -- to save some money for other areas.
X-factors
1. Payroll rising? The D-backs' Opening Day payroll this year was around $95 million, and when all is said in done, it could wind up being close to $110 million next year. The team has about $60 million in committed payroll for 2018, and when you factor in money that will go to arbitration-eligible players, it appears to leave very little wiggle room. Managing general partner Ken Kendrick, though, has never been cheap when he feels like his team can contend, so it's unknown just how high he is willing to take the payroll.
2. A big move? If the D-backs want to re-sign Martinez, they will likely need to move some money to do it. The biggest contract, of course, is Zack Greinke and the $126 million he has coming to him through 2021. Moving a contract of that size is not easy and often requires the trading team to pick up some of the salary. If the D-backs feel they are contenders in '18, would they move their ace? They could look to make other moves -- lefty Patrick Corbin is projected to get $8.3 million through arbitration and outfielder A.J. Pollock, $8.5 million -- but would making those moves to afford Martinez make the D-backs better or worse?