Matusz actually did not have the worst season ever.

Steve Blass

Much has been made of Brian Matusz' ERA of 10.69 being the worst ever for a pitcher who has started at least 10 games and logged at least 40 innings.  However, why are we using ERA here?  It seems quite intellectually lazy (and I had done it a week or so ago), but why use a statistic that most of us recognize as being highly flawed when there are far better ones available?  Probably because it makes an easy and sensational point.  However, I plan to make ammends.  According to rWAR, Brian Matusz will likely finish with the 66th worst season for a pitcher at -2.6, tying such luminaries as Jim Bullinger, Ross Grimsley, and Dick Pole. 

That is a horrible season.  There are probably about 200,000 seasons on record for a starting pitcher with 10 starts and 40 innings, so scoring in the 0.03 percentile is bad enough without resorting to a misguided statistic like ERA.  It should be noted that Matusz had a long way to go before he assumed the worst rWAR ever for a pitcher.  The worst season is Steve Blass at -5.8 rWAR.  Matusz would have needed 112 innings pitched to have achieved what Blass did.  Blass accomplished his feat in 88.2 innings.  Matusz was bad, but he was not Steve Blass bad.

Using the 200 worst rWAR seasons on record for starting pitchers, I created a rWAR-A by divided rWAR by innings pitched and multiplying that by nine.  By turning it into a rate statistic, we can normalize pitching opportunity and hopefully put all of these pitchers on equal footing.  The following are the worst seasons for a pitching according to this rate (min 10 games and 40 innings pitched):

1. Steve Blass 1973 -0.592
2. Andy Larkin 1998 -0.558
3. Brian Matusz 2011 -0.476
4. Luis Mendoza 2008 -0.442
5. Micah Bowie 1999 -0.441
6. Roy Halladay 2000 -0.429
7. Cal McLish 1944 -0.407
8. Dick Conger 1943 -0.365
9. Tony Kaufman 1927 -0.362
10. Hideo Nomo 2004 -0.343

Other Orioles
63. Dave Johnson 1991 -0.214
111. Jeff Ballard 1991 -0.168
151. Jack Fisher 1962 -0.130
160. Dennis Martinez 1983 -0.124

What we can take home from this is that we have witnessed one of the worst seasons on record for a pitcher, but, alas, not the worst.  Rough year for Matusz.  I hope he gets himself back on track.