Wednesday, July 16, 2008

Brewers Struggle Against Bad Pitchers?

Miller Park. The local watering hole. My brother-in-law's house. No matter where I've been lately, it's always the same. If a conversation is struck up about the Brewers' chances of a post season appearance this year, it never seems to take long before someone says, "Yeh, if they can just figure out how to hit bad pitchers." So ingrained in Brewers lore is this belief that evidence supporting it isn't even necessary. Everyone knows it's true, right?

Well, as the resident skeptic of all things assumed in baseball, you'll have to excuse me if I want to see if the facts support the theory. But how do we do that? The first thing we need to do is define what exactly a "bad pitcher" is. Is it a starting pitcher with a bad ERA at the time of his start? Not necessarily, as a pitcher with a 6+ ERA in June may not really be that bad of a pitcher. ERA just can't be trusted over a short period of time. We need something better.

What we really need to use is an updated ERA projection for each pitcher, which is our best guess at their true ERA (their ERA without the sample error). Now, I could use this method to update each of the pitcher's 2008 Marcel projected ERA to account for their performance this year but that's a little too much work. I'm going to do it a bit more crudely. I'll simply take a weighted averaged of their 2008 Marcel projection and their 2008 ERA. The exact weight I used is dependent on the number of innings each pitcher has worked this year but it works out to roughly to a 70/30 split for most pitchers. Not perfect but good enough for the task at hand.

Now, all all we have to do is find the worst projected starting pitchers from the first half of the season and see how the Brewer batters did against them. Here's every start against a pitcher with a projected ERA over 4.75:

In 19 games, the opposing starters had an updated projected ERA of over 4.75. Their average projected ERA (weighted by the IP of their appearances) was 5.12. Brewer batters hit them for a 5.42 ERA. The Brewers batters feasted on bad pitching!

But hold on a second. Of those 19 starts, the Brewers only beat the projected ERA in 8 of them. That's terrible, right? Not really. When a bad pitcher gets tagged for 5+ earned runs (as they invariably do at least a few times a year), it doesn't take many of those kind of starts to kill their ERA. Bad pitchers still have plenty of good starts. Let's look at a couple of the worst pitchers on that list. Josh Fogg? 5.01 career ERA. Despite that, in 42% of his career starts, he gave up 2 or less runs (min. of 5 IP). Mark Redman? Career ERA of 4.85. 2 or less earned runs in 5+ IP in 43% of his starts. A quality start, 48% of the time. That shouldn't be surprising, though. That's just how baseball works.

And for anyone who thinks that projections are the work of the devil, the Brewers have done fine against pitchers who have a bad 2008 ERA as well:

It's frustrating to watch a starting pitcher with a bad ERA do well against the Brewers but it happens to every team fairly often. That fact may not make it easier to watch but it's certainly not unexpected. So the next time you hear that Brewer batters stink against bad pitchers, send them this link!

Wednesday, July 09, 2008

How Much Did Aquiring CC Raise the Chances of a Playoff Appearance?

According to MGL:

"MIL (Increased their chances of making post by 16%, by acquiring CC.)"

The Book Blog: With all the talk of parity in baseball this year…

Dixieflatline estimated the post season appearance improvement at 10%, but I think the 1.5 win improvement he used was a tad low. I had it at about 2.5 wins and MGL pegged it at between 2.0 - 2.5 wins. 16% sounds right to me. Slightly better than a coin flip chance at this point.

Does 16% justify the move? There's a lot of factors to consider and this article considers most of them but leaves one important one out. How much did adding Sabathia improve the chances of the Brewers succeeding in the post season? I'll try and tackle that question soon.

Monday, July 07, 2008

How Much Will Sabathia be Worth in Wins?

Here's my guess:

Pretty straight forward stuff. I assumed a 3.25 ERA for Sabathia in the NL and a 4.75 ERA for Bush, going forward. I also assumed that the offense would continue scoring at the same rate they have through 88 games (4.6 runs/game). To calculate the win percentage, I just used James' Pythagorean (with a 1.82 exponent).

It might be McClung who is ultimately taken out of the lineup, which may or may not have a larger impact, depending on who you ask. The addition of Bush or McClung to the bullpen will be a net gain, though, so this trade may be worth closer to 2.5 wins when all is said and done. That may not sound like much but going from 89 wins to 91 or 92 wins is definitely the sweet spot when it comes to making the playoffs.

And please, don't tell me I'm not accounting for the positive psychological impact this trade will have on the whole team. It may or may not have a significant impact but I doubt it will and there will be no way to prove it, regardless. As a result, I'm assuming (as I have to), that the psychological impact is zero wins.

The trade is a huge gamble but one with a potentially huge payoff. Heck if I know if it was the right move. Only time will tell.