KANSAS CITY -- The foundation for the Kansas City Royals' return to baseball's elite the past two seasons has been an overpowering bullpen.
Good as it has been, however, Royals manager Ned Yost has a word of warning for the rest of baseball.
"The bullpen might even be better for us than last year," he said.
And that was after a season-opening 4-3 victory against the New York Mets in a World Series rematch Sunday night. That was after Joakim Soria's return to Kansas City was marred by him giving up more runs (three) than he got outs (two) in the eighth inning.
That is without Greg Holland, who earned an American League-best 125 saves the three previous seasons. He was sidelined in mid-September by Tommy John surgery and went unsigned as a free agent in the offseason.
That is without Ryan Madson, who returned to the big leagues last season after a three-year absence to give the Royals a legitimate fourth arm to finish off the final three innings of a game. He signed a three-year, $22 million deal with the A's.
But it is with Wade Davis, who took over the closer role in Holland's absence in the postseason and then opened the season with a scoreless ninth for the save.
Since the start of 2014, when he became purely a reliever, working the eighth inning prior to the loss of Holland, Davis has a 0.96 ERA, including Sunday's season opener, and has allowed a .148 batting average, striking out 189 batters in 140 1/3 innings.
That is with the return of Soria, a former Royals closer now being asked to handle the eighth inning. He was an All-Star twice from 2007-11 in his first Kansas City run, saving 160 games. Soria's career was interrupted with elbow problems in the spring of 2012, but he bounced back well enough the Royals signed him to a three-year, $25 million deal in the offseason.
"We have 161 [games] to go," Soria said after the opener. "There's plenty of baseball left. I can pitch better."
Soria did have a 2.86 ERA with Detroit and Pittsburgh after his July 2014 trade from Texas, which is in line with his 2.63 ERA of his career, five seasons of which were spent with Kansas City.
The Royals also return seventh-inning mainstay Kelvin Herrera and right-hander Luke Hochevar, the first overall pick in the 2006 Draft, who is ready to assume a heavier workload this year after being carefully brought along a year ago in his return from Tommy John surgery.

"We feel confident in the late innings," Yost said.
• Hochevar stays cool, extinguishes Mets' fire
The rest of baseball has noticed. That's why teams are now scurrying to add bullpen depth, looking for pitchers who in times past might be considered an eighth-inning setup man to bring into the seventh-inning role. With the world of analytics limiting the willingness of teams to allow a starting pitcher to face a hitter more than three times, there is added importance to that seventh-inning bullpen role.
And it's hard to argue with the success Kansas City has had.
In winning back-to-back AL pennants, losing to the Giants in seven games in the 2014 World Series and beating the Mets in five games last fall, the Royals' bullpen led the Majors with a .224 batting average allowed, a .640 OPS against and a .644 winning percentage. They have an AL lowest .277 average allowed on balls put in play, and lead the league with 109 saves, a 2.987 ERA and a 77.3 percent success rate in converted saves.
It is a big part of why the Royals were able to end their 30-year championship drought in 2015, and whey they go into '16 looking to become the first team other than the Yankees to claim back-to-back titles since the 1992-93 Blue Jays.