Shields will start his second opener in a row for the Royals -- this once coming on March 31 at Detroit -- and his selection was expected.
"Any time you get an Opening Day assignment, it's an honor. No doubt about it," Shields said.
Guthrie was Yost's pick for the Royals' first game at Kauffman Stadium, which will be jam-packed on April 4 against the White Sox.
"I want him starting Opening Day [at home]," Yost said. "He's done it before, he's experienced at it. It's a good matchup, and it's an important day for our fans. Jeremy had a tremendous year last year."
Yost also said Jason Vargas, the free-agent left-hander signed over the winter, would start the second game at Detroit. The home opener is the season's fourth game, so starters have yet to be named for the third or fifth game, although Bruce Chen would be slotted for one of those.
Davis, who began last season in the Royals' starting rotation and then finished in the bullpen, was taken out of the competition for the final rotation spot and was assigned to relief duty. It means that the fifth spot likely will go to either Yordano Ventura or Danny Duffy.
The decision to assign Davis to the bullpen was prompted by the loss of Luke Hochevar to Tommy John surgery on Friday.
"[Davis] is a dominant factor down there for us, and once we lost Hoch, it became apparent to me that [Davis'] presence was sorely needed down there," Yost said. "He had been pitching as well or better than any of the candidates for that rotation spot, but as soon as Hoch went down, we all knew Wade could be a good Major League starter … but we felt Wade in the back end of our 'pen is going to be more productive for us as a team."
Although Hochevar and Davis were candidates for the fifth starter's job, it was clear that Yost had been partial to having them back in the bullpen.
"I just sat and looking at our 'pen at the end of last year, how dominant it was, and it included Wade and Hoch, and I just couldn't see us going forward with a real strong bullpen without Wade and Hoch in it." Yost said. "I sat there last night and decided now's the time to do it."
Of course, while Davis was in, Hochevar was, by necessity, out. Davis, after 24 starts last year, was moved to the bullpen in September while the Royals were chasing an American League Wild Card postseason berth.
"It's best for the team right now and something where we're going to move forward and get ready for the season," Davis said. "It'll be good for the team, and we'll have a lot of fun."
Yost said that Davis will be primarily a late-inning reliever and won't be considered a swing man who could be called upon to start if necessary.
"And he does have the ability, on days when Holly [Greg Holland] does need a break, to close games out. He's that kind of reliever," Yost said.
Yost figures that the Royals won't need a possible starter stashed in the bullpen.
"I don't need a swing guy, because the guys we're going to have in Triple-A are going to be primed and ready," Yost said. "I'm not going at it that if something happens, we can make Wade a starter. Wade's going to be in the 'pen moving forward."
The bullpen looks strong with right-handers Davis, Holland, Aaron Crow, Kelvin Herrera and Louis Coleman, and left-handers Tim Collins, Francisley Bueno and Donnie Joseph all available.
If the Royals keep 12 pitchers, as expected, there will be seven bullpen spots, and Yost is pondering whether or not a long man will be needed.
"I'm still kind of 50-50 on that," he said. "When I'm looking at the numbers and I'm looking at the quality arms that are coming out of there, I've got to weigh the need for a long man compared to another guy that can come in and shut an inning down."
That role likely would not go to Duffy or Ventura as the loser of the battle for the fifth spot. General manager Dayton Moore is on record as favoring either young pitcher going to Triple-A Omaha rather than pitching out of the bullpen. That way if a starter was needed during the season, he would be ready. Moore did say, though, that he was staying open-minded on the matter.
"I am, too, but I probably share that thought," Yost said. "That way you've got guys down there [at Omaha] that are built up and, boom."
Among possible long-man candidates are left-hander Everett Teaford and right-hander P.J. Walters.
Although clubs sometimes skip over the fifth starter because of frequent open dates in April, Yost doubts the Royals will do that in 2014.
"We're talking over a bunch of scenarios, but it doesn't really benefit us to do it," he said.