Posted by BaconSlayer09 (This article was written on September 25th, not all stats are up to date)
Not so long ago, I came across some fans who wanted to see Trevor Cahill win the AL Cy Young, if not finish in the top 5. This is understandable, as Cahill is currently 17-7 with a 2.81ERA and a 1.07 WHIP. There is no denying how good Trevor Cahill has been this year–he’s been very good–as shown by the above numbers. However, what if he played on another team? What if we were to take out numerous dependent factors from Cahill’s stat line? How good of a pitcher would he be? Let’s find out.
First thing’s first, I want to say that Cahill has drastically improved as a pitcher this season. His 2009 was very disappointing, but he has turned himself into a pretty respectable pitcher this year. Now, on to business. Trevor Cahill, at best, has been a good, but not great, pitcher this year. This is shown by his 4.18 FIP (Fielding Independent Pitching ERA) and 4.17 xFIP (x is for expected). His ERA – FIP is -1.37, the highest mark in all of baseball, meaning that he has been incredibly fortunate this year. Unlike ERA, FIP is a predictive stat. As all statisticians know, predictive value in a statistic is extremely crucial. However, in the case of Cahill, his ERA run might continue and FIP could be totally wrong (for a reason, too). And that’s completely fine, FIP is not the end all be all, it is just a factor we can look at to see what’s really going on.
Since the ‘FI’ in FIP stands for fielding independent, something tells me that I should look at how good that Oakland defense is. But before that, we should look at the amount of fly balls, ground balls, and line drives Cahill gives up to assess how much of the defense he utilizes. As of today, Cahill has given up 14.2% line drives, 56.4% ground balls, and only 29.4% fly balls. His 56.4% GB rate is second in all of baseball behind only Justin Masterson (we’ll get to him later). These rates all result in a measly, league leading, .226 BABIP. Nevertheless, this BABIP is not only the result of his low line drive rate, it is also a result of one of the best infield defenses in baseball. A’s infielders have combined for a UZR of 36.2 runs. Daric Barton currently leads baseball in 1B UZR. Kouzmanoff is third at 3B, Ellis is 4th at 2B, and Pennington is 3rd at SS. It is pretty clear that this infield defense is phenomenal. In fact, A’s pitchers lead all of baseball with the lowest BABIP against at .279. So that .226 BABIP Cahill owns is starting to make a whole lot of sense. After all, if you throw 56% of your batted balls on the ground and you have one of the best defensive infields in baseball, you know something good is going to come out of it.
So Cahill is good on the A’s and will probably remain very good with the A’s if Billy Beane keeps this current infield setup and Cahill keeps pounding the ground with baseballs. But let’s just play pretend for a second, what if Cahill wasn’t on the A’s, the best defensive team in the American League? What if he was on the Indians, the worst defensive team in the league? Lucky for us, our experiment has already been done for us. His name is Justin Masterson, he leads baseball in throwing ground balls (60%), yet he owns a ERA a whole two runs higher than Cahill’s and a BABIP 110 points higher. Masterson’s 15.4% line drive rate is not much higher than Cahill’s and Masterson has also given up less home runs (3 to be exact). Thus, Masterson and Cahill are very similar pitchers. Yet, one has 17 wins and a 2.8 ERA while the other is 6-13 with a 4.8 ERA. Moreover, the separation in defense is even more evident when you consider Masterson’s .254 batting average against on ground balls compared to Cahill’s .146 figure. While we don’t have the data to see how hard these balls were hit or where they were hit to, we do know that Masterson has actually given up less extra base hits (doubles down the line) than Cahill on grounders. Thus is the difference between a pitcher who has a 36.2 UZR behind him and a pitcher with a -15.2 UZR behind him. That 52 run differential is actually enough to make or break a pitcher. Yet, Cahill and Masterson aren’t all that different.
There you have it, two similar pitchers, one fortunate, the other not so much. Cahill has been blessed to have such a great defense behind him. If it wasn’t for the group of Kouzmanoff, Pennington, Ellis, and Barton, Trevor Cahill might be 7-17 with a 4.8 ERA, much like Justin Masterson. I don’t want to make it sound like I’m penalizing Cahill for being on a team that does something well, not at all. What I’m trying to say is that in a Cy Young voting situation, you want the best pitcher to win, independent of team factors such as defense and offense. And in the case of Cahill, his success has been heavily dependent on the infield defense behind him. That needs to be taken into account, just like evaluating run support when looking at a pitcher’s W-L record. But that’s for another post at another time.