The Diamondbacks set their Opening Day roster on Wednesday, placing right-hander Takashi Saito on the 15-day disabled list with a calf strain and outrighting left-hander Mike Zagurski to Triple-A Reno.

The moves mean that left-hander Wade Miley will be on the club as the long reliever.

Saito, 42, injured the calf while stretching on Tuesday. Saito underwent an MRI on Wednesday morning, which confirmed he had a medial calf strain, manager Kirk Gibson said.

The move is retroactive to April 1, meaning the soonest Saito could be activated would be April 16. Gibson said the team is hopeful he’ll be ready by then.

Miley posted a 4.50 ERA in 40 innings in the majors last season. He pitched in eight games, seven of which were starts. The club used him as both a starter and a reliever in spring training.

“One of my concerns has been length in the bullpen,” Gibson said. “I wasn’t comfortable without him in the bullpen.”

It’s unclear what the Diamondbacks would have done to fit Miley on the roster if Saito were healthy. Gibson had several reasons for wanting a true long reliever on the team instead of asking left-hander Craig Breslow to fill the role.

“Right now your starters aren’t stretched out as much so you tend to rely more on your bullpen,” he said. “If you come in, Daniel Hudson has the flu and can’t pitch, now what? If you don’t have a guy who can throw you four or five innings, you just blow your bullpen up for days.”

The Diamondbacks weren’t expecting Zagurski to clear waivers, but because he did, he will be removed from the 40-man roster. He had a good spring, giving up three runs in 101/3 innings with two walks and nine strikeouts.

There were no other surprises on the Opening Day roster.

As expected, shortstop Stephen Drew (ankle) joined Saito on the disabled list. The club hasn’t publicly stated a timetable for Drew’s return. He figures he will miss at least a month, perhaps more.

Learning experience

Left-hander Pat Corbin, who was reassigned to Double-A Mobile on Tuesday night, said he’ll head to the minors with a dose of confidence after having proved to himself he can get major-league hitters out during spring training.

“You probably have doubts when you’re not throwing against the guys up here,” he said. “You think they’re big leaguers and they’re that far ahead of you. But you know that you’re getting close when you can come up here and compete.”

Corbin had a 3.00 ERA in 21 innings in the Cactus League, with eight walks and 20 strikeouts.

Never in doubt?

When asked on Monday if Corbin was in the hunt for a rotation spot, Gibson said the Diamondbacks will “always consider changes,” an answer that strongly intimated that right-hander Josh Collmenter’s job was up for grabs.

But Gibson said Wednesday Collmenter’s spot was never in jeopardy.

When challenged as to why he changed his story, Gibson said: “You write what you want. That’s fine. OK, we’re done.”

With that, he left the interview room.

Short hops

Catcher Ryan Budde, infielder Cody Ransom and outfielder A.J. Pollock were reassigned to Triple-A.

&raquo Arizona State coach Todd Graham and Arizona coach Rich Rodriguez will throw out ceremonial first pitches. Both football coaches will debut at their new schools this season.

Josh Collmenter knew everyone’s eyes were upon him with each dreadful start he made this spring. But the only eyes that mattered to him were the two belonging to his manager.

Kirk Gibson has defended him at every turn, although some of the skipper’s comments have been left up to interpretation in recent days.

It got to the point where fans had to wonder if Collmenter’s final spring appearance Tuesday night at Chase Field could be a make-or-break proposition.

If he faltered again, might Gibson instead turn to young left-hander Patrick Corbin and remove Collmenter from the starting rotation? Gibson did, after all, suggest Monday that “things could change.”

Considering Gibson only days ago anointed Collmenter as his No. 3 starter behind Ian Kennedy and Daniel Hudson, that would be a pretty drastic change.

But Collmenter isn’t going anywhere, and he hasn’t lost his job. He said he was reassured of that by Gibson after pitching three innings and allowing no hits and one unearned run during a 5-3 victory over the Brewers in front of 14,270.

“He said, ‘Good job, way to go get ‘em,’ and that everything is on par for my next start, yeah,” Collmenter said, adding of Gibson, “He’s had my back the whole time, and he’s been great about that.

“Now it’s my turn to take the ball and reward his confidence in me and show him he’s making the right decision.”

After the game, Gibson announced that the Diamondbacks had optioned Corbin and fellow lefty Tyler Skaggs to Double-A Mobile and that reliever Takashi Saito had injured his calf while stretching earlier in the day. Saito will have an MRI and be re-examined today.

As for Collmenter, Gibson confirmed that the right-hander will start Sunday’s series finale against the visiting Giants.

Collmenter had an abysmal spring. In his first five starts, he allowed 21 earned runs in 16 innings. He also missed a start because of forearm tightness.

He was much better Tuesday in an effort that featured one hit batter, a walk, a wild pitch and an error by first baseman Paul Goldschmidt.

“I felt really good. I just got back to basics and felt more like myself,” Collmenter said. “The rhythm and tempo was there, and I think that was the big thing I was missing. I was trying too much to figure out why things were happening and I just got back to getting the baseball and throwing it.”

Before the game, Gibson said there wouldn’t be much importance put on how Collmenter went out and threw against Milwaukee.

“I’d like to see him throw the ball better,” Gibson said, “but if he doesn’t, it doesn’t change anything.”

Collmenter was asked if Gibson’s “things could change” comment affected him.

“No. I knew I had to take care of business,” he said. “I didn’t have the greatest spring. That’s on record, and you could look everything up. Going forward now, I can throw all that out the window.

“They don’t keep track of that now. Everybody starts with a clean slate and come Sunday, we’ll just make the charge for another good season for the team and everything that goes with that.”

If Kirk Gibson has a set batting order he plans to roll out for Opening Day, he isn’t telling anyone about it. The Diamondbacks manager plans to do it his way, on his time, and that will be the order of things every time he posts his starting lineup.

And if a player or two gets perturbed about where they are hitting in the order, well, too bad.

“It might bother them, but I don’t think they care,” Gibson said Tuesday before his team’s exhibition game against the Brewers at Chase Field. “They might want to hit somewhere, but they don’t care. They want to win. If it’s not that way, then we’ve got a problem.”

Gibson vowed he won’t tolerate any selfishness.

“I’m confident in my guys. They just want to win, and that’s the most important thing,” he said. “Who cares? You want to win or you want to hit third? Ask yourself. It’s as simple as that.

“Who are we here for? If you want to hit third, then we need to get rid of you.”

Gibson’s lineup Tuesday looked like one fans might see often this season. He had third baseman Ryan Roberts hitting leadoff, followed by second baseman Aaron Hill and right fielder Justin Upton, and left fielder Jason Kubel batting cleanup. Hitting fifth through eighth were center fielder Chris Young, catcher Miguel Montero, first baseman Paul Goldschmidt and shortstop Willie Bloomquist.

Gibson said the Diamondbacks’ goal in 2012 is to “do better than we did last year and become world champions.” If that takes constant tinkering with his batting order, he plans to do it. If it means ruffling some feathers, he will do that, too.

“I’m going to do what I think is right for the team,” he said. “There’s all different types of situations and reasons why I do what I do. Not that I’m always right. I would never say I am. But this game is about overcoming mistakes, whether it’s on the field or whether I make a bad lineup decision. If they’re good enough, they’ll overcome it.”

Asked specifically if he has at least his Opening Day lineup figured out in his head, Gibson couldn’t say.

“I’m not set on it. I know you guys think that’s crazy, but that’s just the way I am,” he said. “It will be that way every day of the year. I might field one right now and tomorrow, I might wake up, take some information between now and then, and it may be the same or it may change.

A new rival

When it comes to rivals, Opening Day starter Ian Kennedy said it pretty much starts and ends with division opponents.

But he can see why Diamondbacks fans will want to root against the Brewers, Arizona’s opponent Tuesday and Wednesday in two tune-up games before the start of the season.

After all, it was Milwaukee that defeated Arizona in their National League Division Series last year. Then-Brewers slugger Prince Fielder also snubbed Upton from taking part in the Home Run Derby at the All-Star Game at Chase Field. And the whole Ryan Braun controversy was the topper.

“Yeah, I can see how our fans view it,” Kennedy said.

Gibson took it one step further, saying before Tuesday’s game: “We owe them. They get us that time (in the NLDS). We need to get ‘em back. … I’d like to beat them any day, starting tonight.”

Gibson said the playoff series with the Brewers was “hard fought, it was clean” and added that he has the utmost respect for manager Ron Roenicke, whom he said “stands for the game the right way.”

“But there’s a little extra on the line when we play them,” Gibson added.

Short hops

Gibson and members of the training staff and medical team met with shortstop Stephen Drew on Tuesday afternoon to discuss Drew’s rehab from a fractured right ankle.

Drew will start the season on the disabled list.

“We just want to determined how hard we push from where he is right now and how quickly,” Gibson said. “We need to make a good decision on that. We don’t want him to come back and go back on the disabled list.”

Wednesday’s scheduled starting pitchers are the Diamondbacks’ Trevor Cahill against the Brewers’ Shaun Marcum.

The Diamondbacks will unveil “Justin Upton Field,” their 31st baseball field in the community through the “Diamonds Back” Youth Field Building Program, on Thursday morning at University Park in Phoenix.

The field is at 1002 W. Van Buren Street. Upton will throw out the ceremonial first pitch at 10 a.m.