Next up in our Pinch Hitters series is Matt Hunter, who recently graduated from Carleton College with a degree in philosophy. He works at a software company in Madison, Wisconsin but does a lot of baseball writing for Yanks Go Yard,  Big Leagues Magazine,  and Beyond the Box Score. 
For his post, Matt found the bright side in a disappointing season.
It’s easy to be pessimistic about Ivan Nova. His ERA jumped from 3.70 to 5.02 in one year, he gave up a whopping 87 extra base hits (compared to 52 in 2011), and he all but fell apart in the second half of the season.
But here’s the thing; I feel better about Ivan Nova’s future now than I did one year ago. You heard me. The 2012 season gave me optimism, not pessimism, about Nova.
Mind you, this is not the same as saying that Nova was better in 2012 than 2011. Why? Because there is a difference between results and talent. Nova had horrible results last season, and those results were largely a product of his performance on the field – no one is denying that. However, Nova showed significant improvement in one essential aspect of his game, an aspect that happens to be the single most important factor for predicting future pitching performance.
I’m referring to strikeouts, of course. In 2011, Ivan Nova struck out 14% of all batters that he faced. In 2012, Ivan Nova struck out 20.5% of all batters that he faced. Using raw numbers, he struck out 153 batters last season compared to only 98 in 2011, despite only pitching five more innings.
More advanced numbers back up these increased strikeouts. In 2010 and 2011, 6.8% and 6.6% of all pitches that Nova threw were swung at and missed. In 2012, that number jumped all the way to 9.0%. A 2-3% difference may not seem significant, but over the course of a season, that’s about 60 additional pitches that were swung through.
That’s nice and all, but why does it matter? Well, strikeouts are the single most stable  aspect of a pitcher’s performance year to year. More stable than walks. More stable than home runs. More stable than wins or ground balls or ERA.
Being stable isn’t enough, though. After all, the number on a player’s back is stable, but that doesn’t tell us anything about the pitcher’s performance or talent. Luckily, strikeouts are not only stable, but tell us a lot about how the pitcher will do in the future. Strikeouts per nine innings has one of the strongest correlations  with the following year’s ERA of all statistics. In fact, strikeout rate correlates better with ERA in the following year than ERA itself!
What does this mean for Nova? Well, first of all, we should expect him to improve if only because almost any pitcher with an ERA that poor will regress back towards the mean in the following year. However, even more than that, Nova’s significant jump in strikeout rate indicates a major improvement in his stuff which, in turn, indicates that he is primed for a bounceback year.
Associated Press photo