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Friday, August 13, 2004

Gobble and K's

As I was perusing The New Bill James Historical Abstract I ran into the article "Bird Thou Never Wert" where James says:

"There is simply no such thing as a starting pitcher who has a long career with a low strikeout rate...I am always amazed that people fail to see this on their own. The career expectation for a strikeout pitcher is so much greater than the career expectation for a non-strikeout pitcher of the same age and ability that the difference is very obvious if you study the issue."

James then goes on to set the bar for a non-strikeout pitcher at roughly 4.00 strikeouts per nine innings.

Because the Royals have a young non-strikeout pitcher in Jimmy Gobble who in his career has struck out 3.50 batters per 9 innings (167 innings, 65 strikeouts), I wanted to see just what that difference was.

To do so I found a group of 69 non-active pitchers since 1945 that started more than 10 games, pitched more than 100 innings, were between the ages of 18 and 23, and had an ERA lower than the league average. This criteria gives pitchers of the same age and same ability at the beginning of their careers. Their cumulative stats were:


ERA AVG W WHIP ERA+ Career W Years Innnings K/9
3.21 9 1.27 84.7 92 11 1557 5.67

where AVG W is average wins in their qualifying season, Career W is their Average Career Wins, Years is the number of years pitched in the majors, Innings is their Average Career Innings, and K/9 is their stirkeout rate in their qualifying year.

When you break these down into pitchers who struck-out fewer batters than the league average versus those that struck out more (I didn't feel using 4 batters per game was appropriate since the league strikeout rates over time vary quite a bit) you get the following two groups.


# ERA AVG W WHIP ERA+ CareerW Year Innings K/9
30 3.25 8 1.28 84.6 56 8 1003 4.44

# ERA AVG W WHIP ERA+ CareerW Year Innings K/9
39 3.18 10 1.26 84.8 120 13 1983 6.61


The most striking thing about these two groups of course is that strikeout pitchers (the second group) won more than twice as many games in their careers as non-strikeout pitchers and had careers that were on average five years and almost 1,000 innings longer. And what's more, as you increase the distance from the league average the gap only gets larger (which James also notes). For example, when looking at only those pitchers +-.25 strikeouts per 9 innings the non-strikeout pitchers have career expectations of 54 wins and 7 years while the strikeout pitchers have 130 wins, 14 years, and over 2,100 innings pitched.

Certainly there a few exceptions in the list of 30 non-strikeout pitchers, the most notable being Joe Niekro who won 221 games over 25 years. Remove him from the list (which is arguably the right thing to do since he was a knuckleballer) and the non-strikeout group moves down to 51 wins and 7 years. The top two pitchers that remain are Bret Saberhagen with 167 wins and Scott Erickson with 140 wins.

So it appears that James was correct. Another way to look at this issue is to look at pitchers with long careers. I selected all those pitchers whose careers started after 1945 who've pitched more than 15 years in the big leagues. Interestingly there were exactly 200 such pitchers. Taken as a group these pitchers struck out an average of 5.9 batters per 9 innings in their first four years when the league average was 5.3.

Why is this the case? James speculates that there are two reasons. First, he says that generally speaking "the batting average against a pitcher is inversely related to his strikeout rate." This is the case since fewer balls are put into play for strikeout pitchers and as we've learned in the past few years with DIPS. Most pitchers don't have much control over the rate at which balls put into play turn into hits. This means that strikeout pitchers can afford to do other things less well (control for example or giving up homeruns) and still be successful. This gives strikeout pitchers more wiggle room as their physical skills decline as they get older. Once they dip much below the league average (historically between 4 and 6.75 from 1950-2004) they are on the way out. As an aside I should mention that the batting average on ball put in play (BABIP) for the sets of pitchers shown above was almost identical at .289 and .290. Secondly, a non-strikeout pitcher is "walking a fine line" since he doesn't have the same wiggle room as the strikeout pitcher. As hitters adjust or the pitchers lose a little ability they are hit harder and are then on their way out.

I don't disagree with either reason. A good general manager should look for young pitchers with decent strikeout rates and trade those who have to walk the fine line to be successful. As far as Jimmy Gobble is concerned, if the Royals bring him back up and he pitches decently I would trade him as soon as possible.

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