Even with eight shutout innings last night Cole Hamels merely lowered his ERA to a still-mediocre 4.52 to go along with a 7-8 record. That represents quite a decline from last season, when he won 14 games with a 3.09 ERA before taking home the MVP awards for both the NLCS and World Series.
However, a closer look at Hamels’ performance tells a much different story than his win-loss record or ERA:
YEAR SO% BB% HR% GB% FB% LD% LOB% MPH 2008 21.4 5.0 3.1 39.5 38.7 21.8 76.0 90.4 2009 20.2 4.8 3.5 42.1 37.4 20.5 73.4 90.2
From left to right, the numbers shown above are strikeout percentage, walk percentage, home run percentage, ground-ball percentage, fly-ball percentage, line-drive percentage, left-on-base percentage, and average fastball velocity. And as you see, every single one of those numbers is essentially the same as last season. There isn’t a meaningful change in the bunch, so how has his ERA ballooned from 3.09 to 4.52? There are a few possible explanations, but the easiest one is batting average on balls in play.
Last season just 27.0 percent of the balls put in play against Hamels went for hits. This season, despite a very similar breakdown of ground balls, fly balls, and line drives, 32.9 percent of the balls put in play against Hamels have gone for hits. Over the course of 25 starts that equals about 30 extra hits falling in, which is worth somewhere around 12-18 runs. And if you remove, say, 15 runs from Hamels’ total this season his ERA drops from 4.52 to 3.59. His career ERA coming into the season? 3.43. Funny how that works.