MESA, Ariz. -- There may be no better compliment paid to the back end of a bullpen than when it’s said: "The game is over after six innings." The world champion Kansas City Royals' bullpen has been described that way. The upstart Chicago Cubs' bullpen is trying to establish the same kind of identity. They’re not quite there, but they believe they are an underrated group.

“The numbers aren’t that much different, but I feel like their guys have been consistent for so long,” reliever Justin Grimm said Monday before the Cubs played the Royals in a spring game. “We’re starting to show that. We should get some publicity for that, but I try not to compare -- it’s about showing up to be there for your team.”

The Royals' bullpen ranked second in baseball with a 2.72 ERA in 2015, while the Cubs' bullpen was eighth at 3.38. The Royals were first in batting average against, while the Cubs ranked sixth. Most statistics are similar, but a closer look at moments late in games reveals that the Cubs were, in fact, every bit as good as the Royals.

Though it’s a much harder comparison to make across leagues, in innings 7-9 both bullpens had the same WHIP (1.16), and Chicago had more strikeouts per nine innings (8.89 to 8.51), fewer walks (2.74 to 3.05) and fewer home runs (0.73 to 0.87). Kansas City had the better overall ERA (3.32 to 3.01) and both teams blew about the same number of saves (20 to 19), but the Cubs aren’t known for their bullpen, while the Royals have several household names.

“They just exemplify it better than anyone else,” manager Joe Maddon said. “They’ve demonstrated it over the last couple of years.”

Despite his tendency to mix roles, Maddon isn’t against having three guys -- like the Royals’ Kelvin Herrera, Wade Davis and Greg Holland -- for innings 7-9. But until he’s confident he has those arms, Maddon will continue to rotate pitchers in and out based on the best matchup, though Hector Rondon is clearly his closer.

“They’ve had this luxury of having relief pitchers in the latter part of the game that didn’t know lefties from righties,” Maddon said of the Royals. “They’ve got neutral, dominant pitchers.”

Hector Rondon has been scuffling all spring, but the Cubs' closer was absolutely shelled Wednesday by the Royals. Rick Scuteri/USA Today Sports

Maddon went on to name his neutral pitchers, including Grimm, Trevor Cahill, Clayton Richard and Adam Warren. But none are necessarily in the same class as the Royals' trio.

“When the Royals' bullpen comes in, the game is over,” Rondon said. “I think we can be like that.”

How far off are the Cubs? Actually, the offense may have a say about that.

“There’s a lot of versatility among the group and you can rest guys,” Maddon said. “The big thing would be not to abuse or overuse them, especially early.”

So what if the Cubs aren’t playing as many close games because their offense is clicking? That’s when Maddon can rest his top relievers. Last season, the offense couldn’t be counted on for six months and the team played in the third-most one-run games in baseball, so guys such as Strop and Rondon were used more often than Maddon would have liked. This time around -- at least in theory -- the Cubs might be able to rest their top guys more.

“We’re not better than them, but we’re close,” Rondon said of the Royals.

Maybe they are and no one quite knows it.