A news conference was held later in the afternoon at Kauffman Stadium to introduce Shields and fellow pitcher Wade Davis, the trade acquisitions from Tampa Bay, before they were whisked away to be poked and probed by doctors in routine exams.
What the assembled media got was a virtual pep rally for the Royals' 2013 season. Yost, flying in from his Georgia farm for the occasion, set the tone when the first question was pitched.
"It just got to a point where we wanted to win baseball games," Yost said. "And these two guys have winning flowing in their veins."
Memo to docs: Make sure there's blood in there, too.
Anyway, the thrust of the big trade is a win-now approach by the Royals. To do that, they sent off two mega-propects, slugging outfielder Wil Myers and pitching prodigy Jake Odorizzi, along with pitcher Mike Montgomery and third baseman Patrick Leonard to the Rays. Shields and Davis (plus a player to be named or cash) were the incoming goods.
Those two, meshed with fellow right-handers Ervin Santana and Jeremy Guthrie, are counted upon to lead a turnaround season for the Royals. Can it happen?
"I think so, we've got all the pieces," Shields said. "You look at our defense and you've got four or five potential Gold Glove candidates, we've got a tremendous bullpen and now we've got some starting pitching. And, from my experience, some pretty good hitting. ... We're just excited for the opportunity. Hopefully, the fans jump on board and get excited with us."
"He pretty much said it," Davis said. "You see it, you believe it and it's got a better chance of happening."
Royals general manager Dayton Moore, who pulled off the deal, said that owner David Glass and team president Dan Glass have given him their full support. After nearly seven years of building up the Minor League system, Moore decided the future was now.
"I felt honestly that this is the time when we have to start trying to win every year. You can say, wait until after '14 or '15 when some of these young players become more established, but the culture has to be created now," Moore said.
"Our young players are going to become the stars that we want them to be and James Shields is going to compete to win a Cy Young with great defense behind him and Wade can grow to be the type of pitcher that he wants to be. So everybody's success is tied together and ultimately I made the decision that it's time to move forward with this group."
Yost conceded that the front four of his rotation seems to be set with the two ex-Rays joining Santana, obtained from the Angels in a trade, and Guthrie, re-signed as a free agent.
Who's No. 5? Yost mentioned right-hander Luke Hochevar and left-handers Bruce Chen and Will Smith.
"We're going to let 'em duke it out," Yost said. "We'll put the guy there that we think gives us the opportunity to win every single day."
Relief duty might be an option for those pitchers as well.
"I think all three of 'em could do that. We'll just see how it plays out. We'll get to Spring Training and let 'em go," Yost said. "Bruce has been very consistent, I think Hoch is still ready to turn the corner. I've said that all along. I think that having Wade and Santana and James here is going to help him tremendously."
Also returning from the 2012 rotation is right-hander Luis Mendoza, but Yost often has said a long relief role could be ideal for Mendoza.
With Myers departing, right field remains in the possession of Jeff Francoeur who struggled last season.
"He's not a dummy, he knew it was a rough year for him," Yost said. "He knew that he needed to bounce back and he's working out diligently to make that happen. So I've got a real good feeling that he's going to come into Spring Training and put together a real productive year for us."
The Royals finished 72-90 last season, in third place 16 games behind Detroit. But at Wednesday's session, Shields noted that the 2007 Tampa Bay club went from last place to the World Series in 2008. Yost pointed to another worst-to-first turnaround by Atlanta in 1990-91 by making key player moves.
"It could be as simple as that. Putting two guys -- four guys in this case, Guthrie, Santana, Shields and Davis -- can make a huge difference and a huge turnaround," Yost said. "Not only with what happens on the field, but what happens inside the locker room."
Shields, who's witnessed what he called a transformation of the Royals from the opposite dugout for seven years, believes that it's possible.
"We know what kind of a team we have here, we're excited. I think the city of Kansas City should be excited. It's going to be a great year," Shields said. "We're going to try to bring that winning culture back here to Kansas City."