SP1 - Zack Greinke: The 2009 Cy Young Award Winner headlines the rotation. Greinke made 136 starts in the '00s, posting a 3.73 ERA over that span, good for a 120 ERA+ and an average WAR of 5.1. As we've covered here before, Greinke's comeback didn't start in 2009, and that wasn't his first strong season. Thus, even on average, he's still the ace of the staff, just a bit closer to the rest of the bunch.
SP2 - Gil Meche: The second and final obvious choice for the all-decade rotation. In three seasons Gil gave the Royals a 4.12 ERA (108 ERA+) and an average WAR of 3.6 wins above replacement. His K/9 numbers (7.0 to 7.6) and HR/9 (0.9/9 to 1.0/9) are comparable to Greinke's, listed second in the parenthesis.
SP3 - Jeff Suppan: And.... now we're in the true Royals of the '00s zone. For three seasons in the '00s (00-02) Suppan gave the Royals a league average ERA (102+). Suppan was pretty homer-prone back in those days, and his 1.3 HR/9 average isn't going to help a staff that already struggles a bit with the longball.
SP4 - Paul Byrd: The selection committee goes with an all-time one-year wonder for the Royals (although Byrd technically pitched in parts of two) who was a Royal star in 2002. Overall, Byrd's as a Royal averages are a 3.95 ERA (ERA+ 125), not many Ks at 5.0/9 and a bit of homeritis (1.3 HR/9). His 3.7 WAR in 2002 is right in line with Meche's tenure.
SP5 - Brian Bannister: A tiny bit of presentist bias might be at work here. Bannister has been good for the Royals, though his ERA is still below league average for the period (92 ERA+). According to WAR, he's averaged 2.3 wins above replacement in his three seasons as a Royal starter. I don't have the WAR data for the early decade on hand, but in terms of the brutal prism of ERA, Darrell May might be a better choice. Between 02-04, May posted similar, if not better numbers (101 ERA+) and should get bonus points for contributing to the one interesting Royal team of the decade.
Setup Man - Jeremy Affeldt: The committee went with Affeldt here, perhaps giving a nod to the million internet and talk radio discussions occasioned by Affeldt's time in Kansas City. Affeldt was good out of the bullpen in 2003, not so much in 2004-5. He's been better in other places, but aside from 2003 was never exemplary in Kansas City, making him a somewhat curious choice. Ramon Ramirez (great in one season with the team) is an acceptable alternative, and Jason Grimsley seems like the obvious one. Grimsley was around forever and was sometimes good. He was definitely more consistently good than Affeldt, but perhaps he's an un-person now because of PEDs and the fact that he seems somewhat insane.
Closer- Joakim Soria: The Mexicutioner. He be awesome. Soria gives the Royals three guys, along with Meche and Zack, who would have made just about any team's all-decade squad.
So basically, this is the 2008-10 Royal pitching staff. High level Zack, followed by Meche and Banny, with Soria closing games. Affeldt is comparable to setup men the Royals have had recently, while Suppan and Byrd are upgrades, but not huge ones. I'm not a huge fan of one-year wonders on squads like this, and as such I'm not sure how to feel about just happening to have the one season when Byrd was way better than he ever was again. I mean, dude threw 7 complete games in 2002. Going to war with two of the Tejeda/Hochevar/Davies guys isn't much different than Suppan/Byrd.
So all in all, its a good, but not overpowering pitching staff, basically the staff of a NL Wild Card team. Things change if we make Zack into ZACK! But of course, 2009 was a historically great season for Greinke. The Royals really need to move the fences back for the All-Decade team. The offense doesn't have a ton of power anyway, and the longball is basically a staff-wide bugaboo.
The 2009 Royals allowed 842 runs, and thats not a terrible starting point for thinking about how the all-decade team would do. All-decade Greinke is a little worse, a few other places are upgrades. Maybe, overall, we get a net 20 run upgrade, though its all very fake, since the all-decade team has a two-man bullpen. So we get the all-decade Royals to ~820 runs. Now, the all-decade lineup looks good to great defensively, especially in the outfield. (Dye, Berroa, & Butler aren't helping.) So lets knock the runs allowed down 770. Considering how many guys give up a lot of balls in play (Suppan, Byrd, Banny) that better defense is big.
I had the all-decade team scoring 826 runs, so this comes out to...
Something like a .532 winning percentage, which is around 86 games.
So the Royals all-decade team would be a fringe Wild Card contender, playing at about 86-76.