Off-day Musings Vol. II - First to 40, But Not Zirconium

Ok, I know it's not an off-day, so the second installment of what I hope becomes a regular fanpost doesn't exactly live up to its name. But I got an idea during my latest endeavor (Infinite Jest - worth the time, Spants!) that I couldn't wait until July 5 to share because I think it is very illuminating and worthwhile as we approach the halfway mark of the season.

The Redbirds are the first to 40 wins in the NL Central. Awesome. But how did we get there? Which way are we headed? Is this first-place position sustainable? Slow down, people. One question at a time.

Let's start with the offense. In O-DMVI, I presented our then struggles in terms of a declining BB% by month. Here, I want to take a more comprehensive look at the offense's contribution to our win total as the season has progressed. I have chosen to do so in terms of WPA (Win-probability added, or the difference in win expectancy between the start of each individual play and the end of the play). Batters' cumulative WPA graphically:

Batters' WPA

As you can see by the bat-with-birds-on-it colored line, we came out white-hot on offense, propelling the team to a great early start. In mid-May, however, we started a disastrous skid that turned our cumulative WPA well into negative territory for the season. Thanks to a recent surge we currently sport a -0.26 WPA on offense, good for 15th in MLB and 7th in the NL. Those numbers are passable, but not anything that is going to get the job done if we have title aspirations. Even more concerning is the fact that if the GOB were somehow to take Albert (and his 3.4 WPA) away from us, we would be sitting at -3.66, 25th in MLB and 11th in the NL. Albert Pujols is ridiculous.

On the flip side of the coin, I don't think anyone could have predicted just how outstanding our pitching performance has been this year. It really hits home when you see pitchers' WPA graphically:

Pitchers' WPA

Wow. Our pitchers really turned it on at the right time, just as our offense began to struggle. The staff has combined for 4.258 WPA, which is 5th in MLB and 4th in the NL. Especially outstanding was the five game stretch starting May 19, where the pitchers put up WPAs of .462, .612, .465, .454, and .369 consecutively. For an elementary lesson for those of you less familiar with WPA and WE, each team starts out with a WE of .500 for the game. So by adding an incremental .462, .612, etc. for those games, the pitchers were basically winning games without help from (and sometimes in spite of) the offense.

Now it probably makes sense to combine the two charts and overlay our W-L to see just how we have navigated our way to the top of the standings:

Combined WPA and W-L

Obviously, when the hitters and pitchers work together, we have had our greatest success, and thankfully the pitchers showed up when the bats were afraid.

Now the fun part: where can we expect to fall at the end of the season? If we extrapolate our previous efforts over the whole season, we get a trendline that looks like this...

WPA trendline

...which accumulates to a total of roughly 93 wins for the season. 93 wins seems about right for this rudimentary projection: our offense is bound to be better and our pitching likely won't be quite as good. That should be good enough to put us right in the thick of the playoff hunt, and with a little luck maybe even a division title. I know vivaelpujols has done some work and regression on how many wins it likely takes in a given year to reach the playoffs, so maybe he can help us out a little.

For fun, here is a breakdown of our best/worst offensive/pitching performances:

Best/Worst of 2009

Go team.


Notes, caveats, etc.

All data taken from FanGraphs.

When I say pitchers, I really mean pitchers and defense.

WPA is by no means perfect. It is important to understand what is being presented here. WPA measures contributions to wins, not actual value, if that makes sense. So the offense and defense could have an awesome day, but each be credited with only half of the .500 WPA. In other words, if the offense is great and pitchers suck, the offense will get more credit in that game than in a game where it was similarly awesome but the pitching was decent. Also, it can be biased sometimes. A-Rod got a huge boost in WPA just by having Castillo drop that fly ball a couple weeks ago (and K-Rod was unduly punished).