The analytical folks may have doubts about the Kansas City Royals. The Royals, however, believe in themselves.

They ended a 29-year postseason drought by claiming the American League pennant before losing to the Giants in seven games in the 2014 World Series. And then last fall, they claimed a World Series championship for the first time in 30 years.

For an encore? Well, the Royals expect more.

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And they don't just talk about it.

It's not just that manager Ned Yost was given a two-year extension through 2018 on Thursday. And general manager Dayton Moore was given an extension of unannounced duration, but believed to be as long, if not longer, than Yost's.

It's that the Royals opened Spring Training this week knowing they have control over their projected roster for not only 2016, but '17 as well.

Oh, there are options for 2017 in the contracts of Edinson Volquez, Kendrys Morales, Luke Hochevar, Kris Medlen and Alcides Escobar, but at least it gives Kansas City the ability to retain any or all of them if the team wants.

There could be challenges in 2018, when Alex Gordon, Omar Infante, Ian Kennedy, Joakim Soria, Chris Young and Yordano Ventura are the only current players under contract, and Kelvin Herrera is the only player who would even be arbitration-eligible.

The Royals feel they are in the middle of a window of opportunity, and they are set to capitalize on it.

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"We believe in and trust our players," said Moore. "You are always going to have to make changes and adjust the roster, but the core is in place."

In place? Left-hander Tim Collins, who underwent Tommy John surgery last March and missed the 2015 season, and backup catcher Drew Butera are the only members of the 40-man roster who Kansas City does not control through at least the 2017 season. They both could become free agents next fall.

That's not a coincidence. While there might have been flashier free-agent outfielders on the market the past offseason, the Royals re-signed Gordon to a four-year, $72 million deal that includes a team option for 2020. He's the foundation of a homegrown lineup nucleus that also includes catcher Salvador Perez, first baseman Eric Hosmer and third baseman Mike Moustakas.

"We have a core that grew up together in the Minor Leagues, which competed with each other and which won together at the Minor League level, and now they are doing it in the Major Leagues," said Moore.

But it's not like the Royals are opposed to going outside for help to fill a void. That's why they signed Kennedy to a five-year, $70 million free-agent deal to step into the rotation with Volquez, Jason Vargas, Ventura and Danny Duffy.

"Obviously you recognize where you are as an organization and evaluate yourself honestly,'' said Moore. "Then you make additions to the team, hopefully with a blend of free agents and the Draft."

So far, so good.

A franchise that has enjoyed three consecutive winning seasons that have included finishing third, second and first in the AL Central and winning a World Series championship, had a winning record only once in the 21 previous seasons.

Even with Moore, it wasn't until his sixth year as a general manager that the Royals won more games than they lost.

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"It is hard to predict the development path of players," said Moore. "It rarely goes to script. You adjust."

And Kansas City has been able to get the revisions to fit together well. The homegrown nucleus has been supplemented by prospects acquired in trade -- like the package that brought center fielder Lorenzo Cain and shortstop Escobar from the Brewers in the Zack Greinke deal back when the Royals were putting a foundation in place.

They have added established free agents. And they have made good on some under-the-radar pitchers, like Young, Ryan Madson, Franklin Morales, Medlen and Joe Blanton, who played roles in last year's success.

"We have tried to do the same thing this year, looking for guys who can complement what we have,'' said Moore.

It's an approach that has worked. No sense in the Royals changing now.