This time I’m going to take a look at a pitcher. Boston’s Clay Buchholz burst on the scene by throwing a no-hitter in his second career start. Boston fans must have been drooling after the Sox won their second World Series in 4 years and teammate and fellow prospect Jon Lester pitched a no-hitter in the beginning of the 2008 season. Since then Lester has gone on to become one of the more dominant pitchers in baseball while Buchholz has struggled in the major leagues and spent significant time in the minors. Until this year.
Buchholz finished 2nd in the AL in era with a 2.33 ERA and went 17 – 7. Meanwhile Lester finished 19 – 9 with a 3.25 ERA. The future for the Red Sox couldn’t be much brighter could it? Lester is a Cy Young candidate and Buchholz just keeps getting better and better. Look at these ERA’s.
If Buchholz is dropping 2 points off his ERA each season we should expect his ERA to be below 1.00 next year right? Well, maybe not, but it should be in the 2.00’s right? I’m going to tell you that it’s much more likely to be near 4.00.
Let’s take a look at some other stats:
Walks per 9, Strikeouts per 9, Home runs per 9, BABIP, and Left on Base Percent
2008: 4.86, 8.53, 1.30, .366, 60.5%
2009: 3.53, 6.65, 1.27, .289, 76.7%
2010: 3.47, 6.22, 0.47, .265, 79.0%
The first number that I want to focus on is Left on Base Percentage. LOB% is the percentage of runners the pitcher strands on base. The league average LOB% is around 72%. In 2009 and 2010 Buchholz had higher than average LOB%’s but numbers that are somewhat reasonable. In 2008 he stranded only 60.5%. That means almost 40% of the runners that got on base against him scored. That’s an unreasonable amount. That low strand rate led to an inflated ERA. So, the improvement between 2008 and 2009 wasn’t as significant as it first looks.
Second, BABIP. League average BABIP is about .295. In 2008, Buchholz had a very high BABIP; lots of balls that should turn into outs were turning into hits instead. Those extra hits lead to more runners, more runs and the low LOB%. Again, his 2008 wasn’t as bad as it looked, and his 2009 wasn’t as much better than his 2008 as it looked.
So, we’ve established that Buchholz’ 2008 was unlucky. Now, let’s take a look at his 2010 compared to his 2009. Two of the most important indicators of a pitcher’s ability are walk and strikeout rate. Buchholz’ rates the last two years were very close to league average as these graphs will show
Guys with average walk and strikeout rates don’t usually post ERA’s nearly half the league average so why did Buchholz? Let’s revisit BABIP and LOB%. Both numbers were a bit on the ‘lucky’ side for Buchholz in 2010 which we’d expect to lead to a slightly reduced ERA. But the number that really stands out is the homeruns per 9. It is much lower this year than Buchholz’ first 2 years in the league. So, the question of the moment is if Buchholz can expect to keep that number low.
The first thing that we will compare it to is the league average. Buchholz was average on walk and strikeout rate how does his ability to control homeruns stack up?
The average number of homeruns per 9 is about 1. Buchholz was a bit above average in 2008 and 2009 but way below in 2010.
Now, certain pitchers can maintain a low HR per 9 rate. Is Buchholz one of those pitchers? The easiest way to avoid giving up homeruns is to keep the ball on the ground. Buchholz does a very good job of keeping the ball on the ground.
Buchholz had the 9th highest groundball rate of all AL starters. So, he should be expected to have a low home run rate. But that low? We can also look at the number of home runs per fly ball.
Buchholz’ 5.6% HR/FB rate in 2010 was the 2nd lowest amongst AL starters. Unless Buchholz has some special ability to keep fly balls in the stadium we’d expect his HR/FB rate to increase next year. Since his HR/FB rates in 2008 and 2009 don’t show this ability I see no reason to expect it to continue.
What happens when we put it all together? We get a guy who has average stuff (as evidenced by his strike out rate) and a guy who has average control (as evidenced by his walk rate). This would lead me to believe we’ll get a guy with an average ERA. The American League ERA was 4.14 last year. Buchholz does keep the ball on the ground, which should limit the number of homeruns that he gives up, in turn reducing the number of runs he’ll give up.
My prediction: Buchholz’ ERA between 3.50 and 4.50