Last winter when the Phillies were revealed as the mystery team that scooped up Cliff Lee off the open market, every baseball mind in the country pondered: Is this the best rotation ever? Dave Cameron chimed in on the topic and concluded this was no case of hyperbole. The consensus around the blogosphere was that entering the 2011 season, Philadelphia had collected the most talented group of starters baseball had ever seen – at least on paper. Even if you only paid attention to the Phillies peripherally this season, you certainly know the trio of Roy Halladay, Cole Hamels and Lee didn’t disappoint. But the label of being the best rotation ever is a towering level to live up to. How did the rotation – on a whole – stack up against its historical competition for the title of “Best Rotation Ever”?

The following numbers and rankings are composed from all of the starts made for each team, not the combination of totals for each player that made a start. Check out the leaderboards here.

21.6% K% (5th ranking of all-time)

The only collective group of starters that checks in ahead of the 2011 Phillies with any reasonable claim as the best rotation of all time is the 2002 Diamondbacks (22.8%). The year following a World Series title, both Randy Johnson and Curt Schilling fanned 334 and 316 batters, respectively. In the heyday of Greg Maddux, Tom Glavine and John Smoltz, the Braves never posted a K% above 20.2% – a rate they hit in 1998.

5.1% BB% (9th ranking since 1916)

We don’t have data before 1916, so this will have to do. Outside of the 2005 Twins (4.3%) who ranked number one on the list, the other seven teams ahead of the 2011 Philadelphia squad were from 1933 or earlier. Checking in again on the Braves, the lowest BB% they could muster with the three future Hall of Famers was 6.1% in 1997.

4.22 K/BB (1st ranking of all time)

It should be no surprise based on the above rates to see the 2011 Phillies grab this spot – and it’s not particularly close either. The 2002 Diamondbacks (3.88) show up in the two spot and the 2003 Yankees ranked third all time with 3.53 punch outs for every free pass. By the time the highest ranking Braves squad appears at the eighth spot with 3.16 K/BB, we’re already down a full integer.

77 FIP- (1st ranking since 1900)

Given that strikeouts and walks are two of the inputs to FIP calculations, you could probably see this coming. The Braves of the late 90’s and the 2002 Diamondbacks fill out the rest of the top five. The 1996 through 1998 Braves were able to find their way into these rankings by their ability to keep the ball in the ballpark – posting 0.70, 0.64 and 0.70 HR/9 rates, respectively – in the most dominating homerun hitting era in baseball history. For reference, the 2011 Phillies gave up 0.69 dingers per nine innings.

74 ERA- (11th ranking since 1900)

There was definitely something in the water on the North side of Chicago before 1920 as the Cubs take the first five spots. The 1998 Braves (73) and 1997 Braves (74) are the only starting squads after 1944 ahead of the 2011 Phillies on this list. While ERA isn’t a good metric for evaluating talent or predicting future results, it does tell us what actually happened.

25.8 WAR (2nd ranking since 1974)

The 1997 Braves claim the top spot here with 26.4 WAR. The 0.6 WAR advantage Atlanta has over this year’s Phillies is partly the result of an additional 32 innings pitched over the full season. The top four pitchers – Maddux (8.2 WAR), Smoltz (6.9 WAR), Glavine (5.4 WAR) and Denny Neagle (3.8 WAR) – provided 92% of the value for the collective group compared to Halladay (8.2 WAR), Lee (6.7 WAR), Hamels (4.9 WAR) and Roy Oswalt (2.5 WAR) who provided 86% of the total. The 2003 Yankees and 2002 Diamondbacks land in the third and fourth spots with 25.4 and 25.1 WAR, respectively. Johnson and Schilling accounted for over 73% of that amount by themselves.

One question that begs to be asked is: How much of this was luck? One way to begin to answer this question is to take a look at a few luck-influenced metrics like BABIP, LOB% and HR/FB. I took the career averages for each of the seven hurlers – including Vance Worley, Kyle Kendrick and Joe Blanton – and combined them into a weighted average based on the number of innings each pitcher threw this season.

For BABIP, LOB% and HR/FB, the 2011 Phillies starters produced rates of .288, 77.6% and 8.1% compared to the weighted career averages of .289, 74.9% and 9.5% that we might expect to see. The BABIP is right in line, but the LOB% and HR/FB do indicate a dimension of luck to the Phillies success this year. Regardless, I’m not concerned with luck because this analysis wasn’t to show if this success was repeatable. The fact of the matter is Philadelphia starters – as a group – put together perhaps the most dominant performance in baseball history this past season.