PHOENIX -- Heading into Spring Training, the D-backs' starting rotation appears set with Zack Greinke, Robbie Ray, Patrick Corbin, Taijuan Walker and Zack Godley.
But who will close out games? Well, that's a lot less certain, and how the D-backs determine their closer will be one of the most intriguing storylines of camp.
Last season, the closer spot was resolved the previous December when the team signed veteran free agent Fernando Rodney to a one-year deal. Rodney showed he still had plenty left in the tank, racking up 39 saves, while Archie Bradley successfully converted from a starter to a dominant setup man.
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Rodney, though, left as a free agent to sign with the Twins, and the D-backs responded by acquiring Brad Boxberger from the Rays and signing Japanese free agent Yoshihisa Hirano.
"We feel like he fits nicely with the other guys we've acquired or currently pitch in the back end of our bullpen," D-backs general manager Mike Hazen said at the time of the Hirano signing. "We feel like he complements them well."
The team has declined to name a closer, but in his one year on the job, manager Torey Lovullo expressed a preference for having one designated ninth-inning pitcher. Lovullo steadfastly stood behind Rodney when the right-hander had a couple of tough stretches during the season.

"I don't know that we'll walk into Spring Training with a declared closer," Hazen said. "We'll probably save that for walking out of Spring Training. I think we have an opportunity to take a look and see what roles best fit everybody."
While Bradley's 1.73 ERA and 79 strikeouts in 73 innings last year seem to make him a logical heir to Rodney, the fact that Bradley pitched more than one inning in 21 of his 63 appearances makes him an intriguing candidate to fill a role like Andrew Miller does with the Indians. Miller pitches in high-leverage late-inning situations with Cody Allen getting the majority of the actual saves.

Hirano, who relies primarily on a fastball/split combination, has spent the past 11 seasons with the Orix Buffaloes of Japan's Nippon Professional Baseball League. Since 2010, the 33-year-old has appeared in 476 games as a reliever and compiled a 2.30 ERA with 156 saves.
Boxberger, 29, posted his best season in 2015 when he led the American League with 41 saves. Health has been an issue for him the past two seasons, but he has the most Major League closing experience of the bunch.
All three have a case for closing, which should make the competition this spring very interesting to watch.