Future Leverage Index

The next thing I wanted to tackle with my Monte Carlo from yesterday was a new metric I am going to call Future Leverage Index, or FLI. Leverage index (LI) and WPA are great for telling you what the current situation is, and how important the next batter is, but what about one or two batters down the line? Many people (including me) have screamed at the TV (or monitor if you are watching with MLB.tv like me) when a crappy reliever is left in the game to face an extremely high leverage situation while the closer blow bubbles with his bubble gum in the bullpen. One of the problems managers have though is relievers need time to warm up so they have to look into a crystal ball to try to determine what the situation will be in a few batters. This is where FLI comes in.

FLI starts with the situation inputed and then runs two league average batters just like it did for the intentional walk tool. Only this time instead of weighting the results with WPA it weights the results with LI. If the half inning ended the FLI is assumed to be zero because you have plenty of time to warm up a new pitcher while you are batting. Averaging all the possible outcomes and you get the FLI for that situation. So like LI, a FLI near zero means it is unlikely that the situation in two batters will reach crisis. As the FLI goes up, the more and more likely a very important situation will occur. A FLI of anything above three probably means you should get your closer up NOW.

Here is a link to a nice table that includes WPA, LI, and FLI. A few interesting situations that I would like to point out. First, the highest leverage situation in baseball is bottom of the ninth, two outs, with the bases loaded in a tie game. This checks in with a LI of over ten but has the lowest possible FLI of zero. Why is this? Because either the batter reached base and the game is over or he made an out and the inning ended. In fact, if you look at most two out situations you will see that they tend to have very low FLIs. This is because even if the pitcher is struggling, it is likely that one of the next two batters will make an out and end the inning. This means that you really should be warming up your important arms early in the inning, not late. Also, if you have a lead and a few runners get on base, and it is getting late in the game, now is the time to warm up your closer. Top of the eighth with a two run lead and runners on first and second checks it at a FLI of 2.9. That is the same leverage as a one run lead starting the top of the ninth. If you are behind by a run though FLI drops like a rock.

Hopefully, the end product of this will be something that is combined with the intentional walk tool to become a situational tool. Plug in the situation and the players involved and it will tell you if you should walk the next batter or to start your closer warming up or whatever. That is still probably weeks away but this should be a good step in that direction.