In the last two months, Joe Maddon has used BJ Upton almost exclusively as the leadoff hitter against left-handed pitchers (something we have long supported). And the reason is simple. Despite his struggles offensively this year, Upton is still hitting well against lefties.
A .384 OBP and a .926 OPS are outstanding. And his totals as a leadoff hitter suggest this has been a smart move by Maddon…
But then a commenter (Gus) brought up an interesting point: Should Upton be leading-off, when in most situations the only lefty he will face is the starting pitcher? In other words, are the 3 plate appearances against the starter worth it if Upton still has to face a right-handed reliever 2 times later in the game when the game might be on the line?
Well, let’s break it down.
So far this season Maddon has used Upton as a lead-off hitter 13 times. Twelve of those were against left-handed starters*. Let’s take a look at how Upton performed against the starting pitchers and the bullpens in those games…
Certainly we have small sample sizes, but
there is a trend emerging. Upton hits very well against the starting pitcher, but is nearly an automatic out later in those games. Is that really a big deal? If Upton helps the Rays out to an early lead, then should it matter how he performs later in the game?
Let’s see if we can add weight to each of his plate appearances. In other words, let’s see if we can determine whether his early at bats are any more valuable than his later at bats. To do this we will use two stats available over at Fangraphs.
Leverage Index (LI): This stat places a value on every plate appearance. The first at bat of a game is more valuable than an at bat in the 9th inning of a 12-0 ballgame. But at the same time, the first at bat of a game is not as important as if there are 2 outs in the 9th and the tying run on third base. LI gives each at bat a value based on the level of importance.
Win Probability Added (WPA): Based on any situation in a game, we can calculate the chance the Rays have of winning the game based on the score, outs and baserunners in any particular inning (Win Expectancy). For example, in the first inning, the chance of winning the game is close to 50%. But if the Rays are winning 12-0 in the 9th, that number is more than 99%. With WPA we can track how much that chance of winning changes after each at bat. So if the Rays have a 50% chance of winning a game before Upton bats and he hits a 2-run double, let’s say that number jumps up to 55% (hypothetically). That at bat alone raised the Rays chances of winning by 5% (0.05). At the same time, let’s say Upton hits into an inning-ending double play. Maybe the Rays chances of winning go down to 45% and Upton’s at bat was worth -5% (-0.05; most at bats have smaller values. See this page for an example).
We summed up LI and WPA for all of Upton’s at bats in which he was used as a leadoff hitter against a lefty and broke them down between starting pitchers and relief pitchers…
First thing we notice is the at bats later in the games (on average) are not more important than those early in the game. For Upton, 64.9% of the plate appearances and 68.2% of the LI came against the starting pitcher.
But his WPA paints a dramatic picture. His at bats late in the game are killing the Rays. His net WPA is almost -40%. That’s a lot. So even though the late-game ABs have about half the LI of the early-game ABs, Upton has been so horrible late in the game, that his overall WPA is about -50%.
In other words, in 12 games as the leadoff hitter, Upton has been worth about -0.5 Wins. And most of that comes against the bullpens. The Rays might be able to tolerate the late-game outs if Upton was putting up huge numbers early in the games. Those numbers against the starters are good, but they are not good enough to outweigh the horrific numbers later on.
This suggests that even though Upton is strong against lefties, maybe he shouldn’t be leading-off against them. And that in turn raises a bigger question of whether it is ever a good idea to have a batter at the top of the order, in front of the team’s best hitters, with such large splits against lefties and righties.
*Actually, 10 were against true lefties and 2 were against Shaun Marcum, a right-handed pitcher. Maddon treats Marcum like a lefty and employs what has been dubbed “The Danks Theory.” So for the purpose of this study, we consider Marcum a “lefty.”