Arrieta and Matusz: BABIP Concerns

There has been a lot of positive talk about Jake Arrieta's start to the 2012 season, and not so much positive talk about the beginning of Brian Matusz's season.  After last night's win against the Yankees, I was shocked to see that Matusz's ERA was down to 4.67 (respectable for the AL bEast).  And then I remembered that I saw Arrieta's ERA on the television screen after his last, and rather disappointing start: 4.45.

I found this to be a shocking considering the praise Arrieta has received so far this year, yet Matusz has been on the front end of a lot of negativity despite being nearly as productive on the mound.  Obviously, ERA is not the best judge of one's pitching ability.  I only brought up their ERA's because they lead to this question:

Are Jake Arrieta and Brian Matusz producing at the same level through 5 starts* in 2012?
*small sample, yes, but still worth a look

2012 ERA WHIP QS IP HR/9 K/9 BB/9 BABIP  FIP xFIP WAR Arrieta 4.45 1.09 2 30.1 1.19 7.12 2.67 0.235 4.06 3.79  0.4 Matusz 4.67 1.70 2 27.0 1.00 6.00 4.67 0.322 4.61 5.30  0.2

The short answer is No, they have not been producing at the same level.  Arrieta has been worth 0.2 WAR more through 5 starts.  Over an entire season of starts, that would result in about a 1.0 WAR difference between them.  But WAR does not predict the future or account for "luck" (BABIP)...

The BABIP data suggests that one of these pitchers has been luckier than the other.  I'm going to make the big assumption that Matusz is back to his former 2010 self (positive thoughts people) for predictive purposes.  When Matusz was on top of his game in 2010, he sported a BABIP of .292, which is common during his successful stretches.  Matusz's BABIP in 2012 through 5 starts is .322.  I do not truly understand all of the advanced metrics and how one effects another, but let's say his luck improves and his BABIP gets down to the .290 range.  He'll likely see a drop in the other advanced pitching metrics, start pitching a little deeper into games, and have more quality starts*.

Jake Arrieta, on the other hand, has been extremely lucky with his .235 BABIP.  His career BABIP is typically in the .280 range.  If his luck takes a turn for the worse and approaches .280, his advanced metrics will not look like those of top rotational pitcher. His current level of production would not be sustainable with a higher BABIP, and he would probably have an ERA in the 5.0 range when the 2012 season is over.

I do not mean to shed gloom and doom on Jake Arrieta.  I just think the Orioles faithful needs to watch the advanced metrics closely with Arrieta and Matusz before judging them.  My bold prediction is that Brian Matusz will have better numbers and be more productive then Jake Arrieta by the end of the year.  I hope Jake proves me wrong and wins 15 games, but I think Matusz is going to surprise his doubters and win between 13 and 15 games with ERA in the 3.9-4.1 range. 

*Side Note: The Quality Start statistic is poor barometer for success in my opinion.  I like the idea of a Quality Start being at least 7 innings pitched with 3 or fewer earned runs.  I think an even better statistic would be a High Quality Start: at least 7 innings with 2 or fewer earned runs.