MINNEAPOLIS -- What took place on Saturday at Target Field wasn't in the Royals' blueprint -- at least the latest revision -- for the 2014 season. Left-hander Danny Duffy wasn't supposed to pitch in relief.

Nope, Duffy had always been a starting pitcher. There was some thought in Spring Training to trying him as a reliever, but in the end, he was sent off to Triple-A Omaha. Keep starting, kid, and we'll call if we need you.

"In this game, things change overnight, and I'm just lucky and happy to have an opportunity to help wherever I can," Duffy said.

After just one start for Omaha, the Royals decided they needed Duffy, but in the bullpen, not the starting rotation. So he jumped on an airplane, arrived just before game time Saturday and finished up for James Shields in a 7-1 Twins win. Now Duffy will be in the bullpen when Kansas City opens a three-game series Tuesday night at Houston.

Early in Spring Training, Duffy made it clear that he was willing to move to the bullpen even as he was considered as a candidate for the fifth starting spot in the rotation. When Yordano Ventura won that competition, there was a debate over using Duffy in K.C. as a reliever or at Omaha as a starter.

"There was a lot of overanalyzing from people who were outside, not in the clubhouse, not with the organization, but I know what I can do," Duffy said.

The 25-year-old southpaw also knew that he had a poor showing in Arizona -- an 11.45 ERA in six games, with six homers allowed.

"They were probably pretty baffled with how it went. I did very poorly in spring, I didn't I have a good spring at all," Duffy said. "I know they were trying to give me every opportunity to make the team, because they know what I could do. But it just didn't turn out to be a good spring for me, so I understood why I needed to go."

On March 23, manager Ned Yost announced it was Omaha and starting for Duffy. On Saturday, Yost announced it was Kansas City and relieving for Duffy. Later that afternoon, it became reality -- Duffy's first big league relief appearance.

"I had a great time coming out of the 'pen," Duffy said. "I was planning to get out there and compete and help where I can. I'm just very blessed to be back here and humbled to be given another opportunity."

Duffy retired all seven batters he faced, but he took 45 pitches to do it, not exactly classic economy of pitches.

"He had a lot of 3-2 counts, but he got through it. That's the important thing," Yost said. "He's going to fit down there nicely, I think."

Six of the seven Twins batters had full counts, but Duffy survived.

"My fastball command, in my eyes, was very good. I couldn't get over the slider a couple of times, but when I did, they were letting 'em go by and they were spittin' on really good pitches," he said. "So obviously I don't want to go 3-2 on a bunch of people like I did, but I can get by with the amount of life I had on my fastball. I basically got through seven hitters with one pitch being commanded."

Watching from the bullpen that day, Duffy got a big lesson in determination and damage control from Shields, who'd absorbed six unearned runs in the second inning, but doggedly continued into the sixth, when Duffy was finally summoned.

"He was a bulldog, he got through 5 2/3 when he could've easily lost his command of everything. He didn't," Duffy said. "He just continued to compete, and I was able to get the ball and come in and try to do the same. And it happened, it worked."

Yost had said in Spring Training that he felt Duffy let too many of his on-field setbacks bother him. Now Duffy seems to realize that as well.

"When I got into trouble in my rookie year, 2012, and even a little bit last year, it was tough for me to have a tough inning like that and then come back out and continue to compete and still make pitches," Duffy said. "Because you get all in your own head; I think I'm past that now. I've really worked hard on my body language and my reactions to things."

Duffy worked on that in his one start for Omaha.

"At Omaha, if I threw a bad pitch, I acted like I meant to throw it wherever it went," he said. "Whereas, in the past when I'd thrown a bad pitch, I was all up in arms -- 'What the heck am I doing?' It's just that the mental part is such a huge part of this game."

In the bullpen, Duffy will have to be able to adjust, too, ready to do anything from protecting a lead to mopping up to going left-on-left to one batter.

"In your mind, when you're out there, you have to think that you can get anybody out anytime, and when my number's called, I'm going to go in there and execute to the best of my ability," he said. "And I'm very confident I can do any role they want me to do."