K%, BB% and the Pirates starting rotation

The Pirates’ starting rotation has been awful in 2010. They rank 29th out of 30 teams in ERA, 30th in FIP, 29th in xFIP, 30th in innings and 30th in strikeouts. From Charlie Morton’s implosions to Chris Jakubauskas’ one scary inning, it has been a tough year to be in the Bucs’ rotation. Let’s take a deeper look, in graphical form.

The most significant aspect of a pitcher’s game is strikeouts. Pitchers that miss bats are able to avoid the pitfalls of balls-in-play variability, and are consistently more successful as a result. Pitchers also must be able to avoid walks. Fewer walks equal fewer free baserunners for the opponent. Thus, the best pitchers generally rack up strikeouts while issuing a low number of free passes. So how do Pirate pitchers stack up against the rest of the league in 2010?

On the graph below, I plotted all 157 starting pitchers who have accumulated at least 40 innings in 2010. That is roughly five starters for all 30 teams. Strikeout percentage (strikeouts/total batters faced) is on the horizontal axis, while walk percentage (walks/total batters faced) is on the vertical axis. I added lines to highlight the overall league average numbers for a starting pitcher (17.3% K, 8.2% BB), creating four quadrants. The bottom-right quadrant represents the league’s best pitchers, those with above average strikeout and walk rates. As you can see, Stephen Strasburg’s tremendous strikeout rate makes him a huge outlier in this area. The upper-right and bottom-left quadrants are the mediocrities, those who perform well in one aspect, but not the other. Those in the upper-left quadrant are the pitchers who make us cringe. You can see that Dana Eveland makes an appearance here, with a strikeout rate of 8.9% and a walk rate of 12.3%. Most of those ugly numbers are obviously from his time in Toronto, as he made just a single spot start with the Pirates. Pirates pitchers are indicated by red points.

Each of the six Pirates has a below average strikeout rate. Most of them are able to stay somewhat competent only by limiting their walks. Outside of Brad Lincoln’s potential to add some strikeouts, there clearly is not much upside in this rotation.