Last week, Rob Neyer challenged someone to find out just how many championships Mariano Rivera has been worth.
I was tempted to go ahead and figure it out, but I didn't really have the time or idea on how do it. Rebecca, over at This Purist Bleeds Pinstripes, decided to go ahead and take that challenge from Neyer. It may be over 4,000 words, but it is definitely worth a read. Rebecca concludes:
When we total up the CONVERTED PREWAR numbers, we get 24.016.
That would be, then, 24 wins.
Now, let’s go back and remember our very basic assumption, that it takes eleven wins to win a Championship.
Twenty four divided by 11 is, of course, just over two.
This means, adjusted to a regular-season scale, the Yankees have won two of their last five World Series, potentially for no other reason than that Mariano Rivera, and not another closer, was on the mound in the ninth inning.
Every time we go and we think that Rivera is the Hammer of God, something else comes around to show us that he’s even greater...
You'll have to click through and read the entire post (do it) to find out how she arrives at this, but I have some gripes with her conclusion and process.
Now, most people would probably do the same thing, but I disagree with this—FIP (fielding-independent pitching) is used to calculate Rivera's playoff WAR (wins above replacement). You will probably be shocked to hear this out of me, but I don't think FIP can accurately portray just how freakin' awesome Mariano Rivera is.
For one, his career BABIP (batting average on balls in play) is .276, so he generally has the ability to outpitch his FIP. His career BABIP is even more astonishing in the postseason, at .229. Now, I have no idea why it is so low in the playoffs, but we're not talking about a small sample size here. Mo has pitched 133.1 innings in the playoffs and allowed only 13 runs. That means he has allowed just 0.876 runs per nine innings in the playoffs. His postseason FIP is awesome, but not nearly as impressive, at 2.23.
Whatever Rivera is doing in the playoffs, it has been working for 15 postseasons. The sample is significant enough that I believe that Mo just is on another level in the playoffs. If I were to try to calculate his playoff value, I would probably have just went with his overall RA/9. This would come closer to showing his actual postseason value.
My other major gripe is with Rebecca's conclusion. She prorates Rivera's postseason WARs into what they would look like over a full season and arrives with her final number of 24. She uses this number to say that Rivera was worth about two championships by his lonesome.
The New York narrative would tell you that this number is accurate, but it didn't seem right to me.
You see, the Yankees have played in 141 postseason games with Rivera on the roster. In the regular season, a replacement-level team would win around 28 percent of their games. In the postseason, the number would be lower, since they would be facing off against the best teams. Just estimating here, but 18 percent sounds fair.
That would leave 116 total WAR available, total, for all of the players in all of those games. While Rivera has been unbelievable, I don't think there is any way we could say that he was responsible for 24 of these total 116 available wins above replacement (~20 percent).
Rebecca will admit she's not really a math/stat-head, and the effort in this piece was extremely valiant. I just can't get myself to agree with the conclusion.