My most recent article suggested that Brett Gardner should be starting over Melky for the rest of the season, and in the postseason. I even suggested that Melky's postseason roster spot may be more aptly used on Freddy Guzman. I received a lot of negative feedback on that, with a lot of people telling me that I wasn't valuing Melky's clutch hitting enough.
I was planning on writing about how just because Melky has been clutch thus far this season, we can't expect him to continue being clutch going forward. Surprisingly, when I actually took a look at the stats, I discovered that Cabrera hasn't even been particularly clutch this season.
This is just one isolated incident that proves something that everyone should know. While you can learn about a team by watching them play every game, as many of us do, you will not be able to adequately quantify how they are contributing to the team without taking a look at their statistics.
When I think of what Melky has done this season, I think of his two walk-off hits and a late home run he had in a tie game. These memories stick out in my mind, but in reality, they don't outweigh the plate appearances where Melky hasn't come through.
Win Probability Added (WPA) measures this exactly. It takes into account the game situation and leverage of every single plate appearance for every single batter and adds it all up. Cabrera has a -0.30 WPA. Zero is the league average. Considering Melky has been a league average hitter this season, I was expecting his WPA to be considerably higher than zero.
Melky actually has been worth more if you strip the leverage away. Melky has been worth 0.22 WPA/LI(Win Probability Added divided by Leverage Index). This results in a Clutch score of -0.53. Since Melky has had a few very clutch hits this year, it is ingrained in our minds that he has been clutch overall. WPA is the ultimate measure of clutchness, and Melky comes out with a negative number. The fact is that he just has not been clutch this season.