February 21, 2012 posted by Matthew Dewoskin

2012 Fantasy Baseball Stats You Should Know: K/9 and BB/9 Edition

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Bud Norris, SP, Houston Astros

Why are stats like K/9 and BB/9 important for fantasy baseball? Well, strikeouts are generally viewed as “good” for pitchers and walks are generally viewed as “bad.” Generally speaking, of course.

Most fantasy leagues usually use strikeouts as a pitching category. Fantasy GM’s should want to know K/9 because it’s a stat that shows which pitcher is capable of racking up lots and lots of K’s. There’s a reason that Brad Penny and Carl Pavano aren’t as desirable as Brandon Morrow and Anibal Sanchez. Penny and Pavano posted the two lowest K/9 ratios in baseball last year and Morrow and Sanchez were among the league leaders.

BB/9 is also important. WHIP is a normal stat for most fantasy leagues and the “W” stands for walks. It’s a good idea to stay away from players with high BB/9 ratios. There’s also a reason why James McDonald and Charlie Morton are considered stay-aways in most formats. They both walk over four batters per nine innings. Dan Haren will always return value because his WHIP will always be lower than it should be. He just doesn’t walk batters.

Now you’re probably saying, “Matt, I don’t care about these ratios because no one throws nine innings any more.” You’re right. Very few pitchers go the full nine any more, but it’s a way to standardize K’s and walks while making them accessible to everyone. It’s a lot easier to see that a pitcher posted a K/9 of 8.78 than a pitcher struck out 197 batters. You need to know how many innings were thrown to know if it’s good or not. 197 K’s in 150 innings is a lot more impressive than 197 K’s in 260 IP.

There is a difference between K/9 ratio and strikeout rate. Even some extremely popular writers have made this mistake. Strikeout rate is the percentage of batters struck out. K/9 is the ratio of strikeouts per innings pitched multiplied by nine. Both are very different and are not interchangeable.

Now, how can we use these stats to achieve fantasy glory? Fantasy GM’s need to be drafting pitchers who strike out lots of batters. Not exactly earth-shattering news, but Chris Carpenter has been drafted in the early rounds of drafts for years, but he didn’t post a K/9 over 7.00 from 2006 until last year. Jeremy Hellickson’s low K/9 (among lots and lots of other reasons) is one of the main reasons that a lot of pundits have him pegged as a bust. Rick Porcello has become a total stay away because of his career average 4.84 K/9. Guys like Joe Saunders and Mark Buehrle aren’t really worth a roster spot in a 12-team mixed league because they will hurt more than they will help with strikeouts. They get lucky and post a decent ratio with a dozen or so wins, but the lack of K’s will put your team at a competitive disadvantage.

Fantasy GM’s need to stay away from pitchers with killer walk rates. A guy who will walk 4+ batters per nine is a stay away. That’s part of the reason that it’s been hard to win with Chad Billingsley. He walks too many batters to make his competent K/9 ratio worth it. Jhoulys Chacin was a popular sleeper pick because of his 9.04 K/9 in 2010. He also posted a BB/9 over 4.00. He maintained his high BB/9 in 2011, but his K/9 plunged to under 7.00.

A way to conduct pre-draft research is to look at the average draft position charts and identify pitchers with high K/9 ratios and reasonable BB/9 ratios that are being undervalued. A couple names that fantasy GM’s might want to take another look at are guys like Bud Norris (8.52 K/9, 3.39 BB/9), Ryan Dempster (8.50 K/9, 3.65 BB/9) and Mike Minor (8.38 K/9, 3.27 BB/9).

There are some exceptions, the most notable of which pertains to young pitchers. One of our general rules for young pitchers is that BB/9 does not matter as much. As a general rule most pitchers improve their BB/9 as they get older, for obvious reasons, and when you are looking for sleepers a great way to find them is to find a player with a high K/9 and a high BB/9, but where the BB/9 is on a downward trend. This was one of the new theories discussed at the old Fantasy Baseball Generals blog that has since been proven. The aforementioned Norris is a great example; another is Brandon Beachy this year.


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