Yost gave his son the names of pitchers Jeremy Jeffress and Jake Odorizzi, shortstop Alcides Escobar and center fielder Lorenzo Cain -- the four players who were sent to the Royals for Greinke and shortstop Yuniesky Betancourt.
"And he said, 'My gosh, you're taking our whole future,' " Yost continued. "And I said, 'Well, you guys are getting Greinke.' And he said, 'Yeah, I guess we are.' So they're all four pretty special players."
The Royals will begin to find out how special as camp opened on Tuesday with the first scheduled workout for pitchers and catchers. They reported on Monday but, in fact, 32 of the 33 pitchers on the Spring Training roster were already at work at the Surprise, Ariz., complex last week.
The radar-gun-igniting Jeffress was among them.
"This kid can some kind of bring it," Yost said.
Odorizzi, who has no experience above Class A, will be working out later with the Minor League players. Escobar and Cain will be among the rest of the squad due to check in on Friday and begin workouts the next day. Several position players, including first baseman Billy Butler and left fielder Alex Gordon, were already on hand this week at Surprise.
The big story among the pitchers is the massive influx of youngsters, most of them from the Royals' top-rated farm system. Eight of them are 22 years old or younger. Four are 23. Of those 12, eight happen to be left-handed.
The youngest is John Lamb, 20, who was so impressive in 2010 -- he was the Royals' Minor League Pitcher of the Year -- that he could make a serious bid for the Major League roster. You could pencil in a lot of names in that category and, if they don't crack the rotation, they just might get into the bullpen mix behind setup man Robinson Tejeda and closer Joakim Soria.
Certainly Yost and pitching coach Bob McClure will be keeping an open mind to that possibility.
"We may have a guy who has been a starter the whole time in the Minor Leagues and we may put him in the bullpen, let him get his feet wet and maybe halfway through the season begin to incorporate him into the rotation," McClure said. "I was brought up that way. A lot of guys were."
Count a kid like Nathan Adcock, a Rule 5 pick from Pittsburgh, in that group. He's been a starter but, as a good strike thrower, he could fit into the bullpen. There are certainly others such as Aaron Crow, Everett Teaford, Danny Duffy, Chris Dwyer, Mike Montgomery and Will Smith. And there are youngsters who have been primarily in the bullpen such as Tim Collins, Blaine Hardy, Patrick Keating and Louis Coleman.
McClure has been observing the youngsters limbering up at the complex.
"This is the first year I've seen this much talent," he said. "Where they'll end up, I don't know. Some will end up in Double-A, some will end up in Triple-A, and a couple will end up the big leagues, I'm sure. What'll be interesting is how they handle the games because a lot of them haven't pitched past Double-A."
The first Cactus League game will be Sunday, Feb. 27, against the neighboring Texas Rangers at Surprise Stadium.
McClure has been impressed so far with the throwing of newly signed left-hander Jeff Francis, who is entering his second full season after shoulder surgery, and Soria, who is coming off a 43-save year.
As usual, Soria was on target.
"He threw 30 pitches and missed the target one time," McClure said. "He looked really good."
Several of the younger pitchers also dazzled him.
"The guy that surprised me the most so far was Duffy. He's under control and hitting his targets pretty good. Last year, he was out of control and just chuckin' up there as hard as he could," McClure said.
With Greinke gone, the rotation is topped by Luke Hochevar with veterans Francis, Kyle Davies and Bruce Chen figuring prominently. Newcomer Vin Mazzaro, who came from Oakland in the trade for outfielder David DeJesus, and Sean O'Sullivan are also in the running.
"We have a base but a lot of the young kids, I'm sure, are coming into Spring Training trying to push," McClure said. "Competition is good. It's good to have young talent behind you pushing you."
There aren't many "oldsters" at all among the pitchers. Chen, at 33, is the elder statesman and Francis, 30, is the only other pitcher out of his 20s.
The entire group is healthy, according to McClure, including two pitchers on a rehabilitation schedule -- Noel Arguelles, the Cuban left-hander who underwent shoulder surgery, and Zach Miner, the former Detroit right-hander who had elbow surgery.
The catching staff is headed by the club's oldest player, Jason Kendall, 36, but he's coming back from shoulder surgery and isn't expected to be ready before May. The other catchers on the roster, if not exactly fuzzy-checked, are comparative babies in terms of Major League experience.
Brayan Pena is 29 but has started just 76 games behind the plate in five Major League seasons. Lucas May, 26, last year started the first nine games of his brief big league career. Manny Pina, 23, has no time in the Majors.
Also in camp as a non-roster player will be Salvador Perez, considered the top catching prospect since Wil Myers was converted to the outfield. But Perez has not played above Class A, so he's probably a couple of years away.
McClure sees that the youngsters are arriving in camp with an attitude. A winning attitude.
"A lot of these kids have won wherever they've been -- A-ball, Double-A, wherever they've been. They're used to winning. They have that kind of attitude because that's all they've ever done is win," he said.
"They expect to win and they're the ones out there doing it and that's really nice to see."