KANSAS CITY, Mo. -- The Kansas City Royals gambled their future Sunday night for a chance to win right now.

The Royals acquired former All-Star James Shields and fellow right-hander Wade Davis from Tampa Bay in a six-player deal that sent top prospects Wil Myers and Jake Odorizzi along with two other minor leaguers to the Rays.

The swap immediately bolsters the Royals' starting rotation and should make them a contender in the relatively weak American League Central.

"We have to start winning games at the major league level, and the way you develop a winning culture is by winning major league games," Royals general manager Dayton Moore said. "It's time for us to start winning at the major league level."

Kansas City, which hasn't had a winning season since 2003, has long had one of the best farm systems in baseball, and slowly the cream has risen to the big league level. But there has remained a dearth of starting pitching that has hampered the Royals' chances for success for years, and Moore wanted to solve that problem this offseason.

He's already re-signed Jeremy Guthrie to a $25 million, three-year deal, and took on former All-Star Ervin Santana and $12 million of his contract from the Angels. But the trade for Shields and Davis is Moore's most aggressive move yet, giving Kansas City the ace it has been lacking since trading away Zack Greinke, along with another piece that could fit in the rotation or the bullpen.

"When you can acquire a pitcher like James Shields and Wade Davis, we have to do it, because that's what we've committed to our team -- we've committed to our organization," Moore said. "It's important that we start winning games."

Along with giving up Myers, widely voted the minor leagues' top player last season, the Royals also traded away Odorizzi, a talented right-hander who would have competed for a spot in the Kansas City rotation this season. Left-hander Mike Montgomery and third baseman Patrick Leonard also are headed to the Rays, while the Royals will receive a player to be named or cash.

"We're constantly working to balance the present and the future, and always trying to thread the needle," Rays executive vice president of baseball operations Andrew Friedman said. "As an organization we rely more on the contributions of our young players basically than anyone else in baseball, and with this trade we're hoping to replenish our system and add a lot of players we feel can help us sustain this run of success that we've had for the last five years."