GLENDALE, Ariz. -- D-backs manager Torey Lovullo has a good idea of who his Opening Day starting pitcher will be, but he's letting spring dynamics play out a little longer before making an announcement.
"We have one really good candidate, and everyone knows who that is," Lovullo said, carefully avoiding a spoiled surprise by making sure not to mention Zack Greinke's name. "He has some concerns, and we want to listen to those concerns and make sure he's comfortable. Not that he's hurt. Not that we're concerned about anything like that. We're concerned about where he's at."
Greinke has raised his own questions about his velocity in early March, and though it's nothing unusual and raises no red flags for the D-backs staff, Lovullo does want to listen to Greinke and take him seriously.
"Zack has a process, as we're all getting to know him," Lovullo said. "This is exactly what he was doing last year. The velocity was slowly creeping up start by start.
• D-backs Spring Training: Info | Tickets | Schedule
"My concern is minimal, considering the guy and what I know of him. I know some really good pitchers and position players that have played in this game a long time that have the same reaction to their days, or a lack of perspective that they have. They get frustrated. They expect perfection. Zack's in that category."
Lovullo stressed that he won't put players in a position they're not comfortable in, but he didn't think Greinke was facing anything as dramatic as begging off an Opening Day start to work on his velocity in an environment like extended training.
:: Spring Training coverage presented by Camping World ::
Streak snapped
The D-backs' six-game Cactus League winning streak came to an end Sunday, as their five-run frame in the seventh fell short of the steady nibbling the White Sox had used en route to a 6-5 victory.
"It's frustrating when you get as close as we did and you can't finish it off," Lovullo said, though he was happy with the offensive potential from a squad that featured only one expected starter.
Southpaw Patrick Corbin limited damage, but allowed three runs on five hits and two walks over four innings.
"I was getting quick on my front side and didn't get some fastballs," Corbin said, adding that he was working on, "Throwing strikes, getting ahead, using my fastball on both sides of the plate. I was attacking the fastball. I know my slider is there, so I was just working on some backdoor breaking balls and some changeups. Overall, I felt good."

Medical tent
Randall Delgado was scheduled to pitch in Sunday's game against the White Sox, but after mentioning an issue with his side session Saturday, the D-backs are giving him a few days off.
"After his throwing program yesterday, [Delgado] talked about a little discomfort on the left side, his left oblique," Lovullo said. "We're going to slow-play it, shut it down until after the off day [Tuesday]. We don't think it's anything that's going to be a worry. The progression has these little hiccups in them that we're prepared for."
If all goes well in his progression the rest of the spring, Delgado should be available for Opening Day.
"We're optimistic that'll be the case," Lovullo said, though he noted he will avoid making matters worse by trying to rush the right-hander back into action. "He's such an important piece of this puzzle. If we rush him back in a situation where we're going to ask for a setback, we're not doing our best job. So we're going to slow-play it and make sure he's OK."
After facing live batters Saturday, Jimmie Sherfy is ready for the next step in his progression toward pitching in a Cactus League game. On Wednesday, Sherfy will pitch in a game on the backfields at Salt River Fields.
Up next
The D-backs host the Rockies on Monday at 1:10 p.m. MST. Zack Godley had been scheduled to start against the division rival, but right-hander Kris Medlen will climb the hill while Godley pitches in a backfield game. Follow the game on Gameday.
Luvollo likes to use pitchers in the more controlled environment of a backfield game, where the length of innings and ups and downs between innings can be adjusted to suit the team's needs, but it's also common to keep starting pitchers from facing division rivals and building up too much familiarity through Cactus League play.