SCOTTSDALE, Ariz. -- The battle to be the D-backs' closer among Brad Boxberger, Archie Bradley and Yoshihisa Hirano rages on, without an overwhelming front-runner having emerged.
"For me, it's wide open," D-backs manager Torey Lovullo said. "It's something where we are watching and evaluating. Like I said from the get-go, the results aren't necessarily going to be a huge factor for us right now. We are watching stuff more than the results."
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Boxberger, who was acquired from the Rays in the offseason, was the first of the three to get in a game when he tossed a scoreless inning against the Rockies on Feb. 23.
That's the last game action he's seen, however, as he experienced some general arm soreness and has thrown only bullpen sessions since, including one Sunday morning.
"It felt great," Boxberger said.
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When Boxberger will get back into a game has not yet been decided.
"I was there to watch it," Lovullo said of Boxberger's bullpen. "It was very aggressive and looked good. It was 25 pitches and he said he felt fantastic. So we'll reassess where he's at in the morning and figure out what the next step of his process is through his eyes."
Hirano, who was signed out of Japan to a two-year, $6 million deal, which also includes $1 million in incentives, did not look sharp in his first two outings as he allowed three runs over two innings.
Sunday, though, Hirano retired the Cubs 1-2-3 in his lone inning. His signature split-finger fastball had late action on it and seemed to have a good deal of deception.

"Hirano's stuff for me was the best that we've seen," Lovullo said. "The fastball command was well-above average. I don't know what the velocity was and I really don't care at this point. I think he spotted his fastball."
The biggest challenge for Hirano is adjusting to the difference between playing here and in Japan, where he spent the previous 11 years.
"It's a little different in Japan," Hirano said. "But I'm all for getting used to the ways we do things here in the U.S."
Meanwhile, Bradley is being stretched so that he can throw multiple innings out of the 'pen if needed.

Bradley tossed a scoreless inning in his first appearance before struggling the second time out against the Giants, when he walked three and allowed four runs in 1 1/3 innings.
Three of those runs, however, scored after he left the game, and he spent time during the outing working on his changeup. Sunday, he worked two scoreless innings against the Cubs and threw just a fastball and curve.
With Boxberger possibly getting back into game action soon, the race looks to be heating up.