So, I compiled a list of the top 5 franchise pitchers for each team and their stats while with that franchise. The pitchers chosen were those who accumulated the most WAR with the given franchise to account for both awesomeness and longevity. For instance, I didn't want the Blue Jays to get credit for more than just 2 years from Roger Clemens. For the sake of comparison, I used only pitchers that played the majority of their careers after 1900 and only used their stats while they were with the team. After compiling all the data from Baseball Reference, I chose the following several teams for whom cases could be made. So with that, lets actually see where the Braves rank.
|Grover Cleveland Alexander||58.2||7||2492||2.12||143||1.066|
As you can see, determining the top all-time rotation is a very subjective process. It all comes down to what you value the most. The Giants have the lowest rotational ERA with every pitcher posting a sub-3.00 clip, but I hesitate to call them the best because ERA by itself can be misleading. ERA must be understood in the context of the run environment of each pitcher's day. A pitcher can benefit tremendously from pitching in an offensively poor era or in a pitcher-friendly ballpark. ERA+ adjusts for those factors, and is set to a scale where the average ERA+ is 100 and an ERA+ of 125 is 25% better than average, etc.
Looking at ERA+, the Red Sox come out #1 by far. Their 3rd lowest ERA+, Clemens, is higher than anyone's on the Phillies, Dodgers, or Giants. And they had Pedro Martinez, who's first 6 years with the Red Sox might have been the best 6-year stretch by any pitcher in baseball history. The problem with the Red Sox, however, is that their best pitchers were with them for only short amounts of time. Almost every one of their pitchers spent parts of their prime on other teams. Their pitchers have pitched the fewest years (44) and second fewest IP of any of the above teams. If ranking the rotations by ERA+, without having done the math, it appears an absurdly close race between each other team above for second place.
If you want to place an emphasis on greatness and longevity with a team, I think the Braves are the clear #1, accumulating more than 50 WAR greater than the next best team (Twins). Spahn, Niekro and Smoltz each pitched 20 years with an ERA+ of 120 or greater, suggesting, at the very least, extreme reliability and consistency outside of their peak years. The really impressive thing about this rotation is that each pitcher spent the entirety (except for 1 Maddux-year) of their quite-lengthy primes with the Braves. And if longevity is a major determinant in the rankings, then I think 2nd place is close between the Giants, White Sox, and Dodgers. You could make an argument for the Twins here, but the majority of their strength comes from just 1 pitcher - Walter Johnson. As transcendent as he was, he remains an outlier on an otherwise below average (amongst the above lists) staff.
Of course, there are other ways to rank pitching rotations and evaluate pitchers careers. One very common way is to only look at each pitcher's prime, his top 6-8 consecutive years while on the team, to bracket out rocky rookie seasons and sub-par, often injury-riddled, career twilights. The pitchers to make the cut would definitely change - for example, I'm sure Catfish Hunter would make it for the A's. Of course, that method would emphasize strength of prime over length of prime, and little credit would be given to pitchers who managed to stay great for a decade or more. Its
Whichever method you choose, I think the Braves stack up against the best of the best. Ranking and arguing about ranking players is always fun.