Middle relievers have been key to the Royals pen success

ESPN's Jayson Stark had an interesting article this week where he attempted to figure out why the Royals seem be defying projection models like ZIPS and PECOTA the past few seasons. He posits a few theories, such as the excellent defensive, the outstanding baserunning, even the coaching. One suggestion is that the dominating Kansas City bullpen is a key weapon to allow the Royals to win more games than you would expect with their overall talent level.

When the Royals have led after eight innings over the past four seasons, they've gone 241-4. When they've led after seven, they've gone 211-10. So when you win pretty much every game in which you take a lead, over that many years, you're defying all probability and all norms of bullpen volatility.

Over the last four years, when the Royals have led after seven innings, they have won 95% of the time. That sounds impressive, even overwhelming. When the Royals carry a lead into the late innings, the game is pretty much over.

But is that much different than the norm? The fact is, when most teams carry a lead after seven innings, the game is typically over. That is why the Royals comebacks are so amazing - it is rare to see a team win late. While the Royals have won 95% of their games when leading after seven innings in the past four seasons, all other Major League teams have won 91% of their games when leading after seven innings, according to Baseball Reference. Even last year, the difference was small, with the Royals finishing out 96% of wins when leading after seven, compared to 92% by the league.

Make no mistake, the Royals are better. But the margin is not that great. If two teams carry a lead after seven innings 70 times in a season, the Royals will win 67 of those games, while the average MLB team will win 64. That three-game difference could mean the difference between a Wild Card berth and sitting at home in October. But this is not the Royals' biggest bullpen advantage.

Let's look at how the Royals compare to the rest of the league when leading after five innings (going into last night's games):

In 2013, the Royals were actually below-average at holding a lead, with Luke Hochevar, Kelvin Herrera, Tim Collins, and Aaron Crow pitching the middle innings. If you take out that year, the Royals have won 90% of their games the past three seasons when leading after five innings, compared to 83% by the rest of the league.

The difference was even more pronounced last year with the Royals winning 94% of their games when leading after the fifth inning, compared to just 83% by the rest of the league. If 70 leads were to carried into the sixth inning, the Royals would be expected to win 66 of those games, compared to just 58 by the average American League team.

The depth of the Royals pen was evident last season. Here are all American League bullpen numbers from last year.

Now what happens when you take away their closer? I subtracted the numbers of the pitcher who led the team in saves.

Without Greg Holland, who served primarily as the closer until he was injured late in the season, the Royals were a half-run better than any other American League bullpen. Sure, the Royals had the best reliever in baseball Wade Davis setting things up in the eighth before moving to the closer's role. But the reason the Royals bullpen was great wasn't so much that they had so many great arms, it is that they had so few terrible ones.

Last year, the Royals had zero relievers with at least 30 innings pitched and an ERA over 4.00, joining the Indians, Nationals, Dodgers and Pirates (the Colorado Rockies had nine such pitchers!) In fact, the only Royals reliever with an ERA over 3.75 was their closer, Greg Holland, who struggled late in the season due to a lingering arm injury.

The Royals bullpen had no holes. If opposing starters go into trouble in the sixth inning, the manager was tasked with the decision of leaving a tired starter out there, or bringing in a crummy swingman just up from AAA. Meanwhile, the Royals could bring in Luke Hochevar with his dominant curveball. Or Kelvin Herrera and his wicked fastball. Or Ryan Madson and his drop-off-the-table changeup. Heck, they even got useful relief innings from Joe Blanton. As Jesse Spector of The Sporting News found when he asked Royals pitchers about the bullpen earlier this year:

"I don’t think you need statistical analysis to determine that if you have six studs in your bullpen, you’re going to be successful," said Royals starter Chris Young

This year, the cast of characters is a bit different, with Wade Davis moving into the role of closer, but the Royals could have the same kind of depth. Danny Duffy has struggled early on this year, but historically has been excellent  coming out of the bullpen. Luke Hochevar should improve upon last year's performance now that he is another season removed from Tommy John surgery. Joakim Soria, who has had his struggles early on, has a solid track record of success. The Royals may even get decent relief performance out of Chien-Ming Wang, who is throwing harder than ever.

Make no mistake, it helps to have the most dominating closer in the league, and Wade Davis is doing his part. But having an elite closer is not what gives the most separation between the Royals and the rest of the league. The Royals gain a bigger edge by having more bullpen depth and fewer bad bullpen options than any other team.