A Few Thoughts About K/9

K/9 is a statistic that has become very important to fantasy owners when evaluating pitchers.  As more and more category leagues either use innings limits or simply substitute K/9 for Ks, a pitcher’s overall strikeout total seems almost irrelevant without the context of how many innings it took for said pitcher to accumulate those Ks.

As we move forward, however, it is very important that we all become aware of the limitations of K/9 as a statistic.  Without understanding the intricacies of how and why pitchers are able to accrue a strong K/9 ratio, prospective owners may fall into the trap of overvaluing certain pitchers on draft day.

The issue with K/9 is that it punishes efficient pitchers when compared to less efficient counterparts.  If two pitchers have an identical K%, the one who faces more batters per inning will have the higher K/9.

Consider the following made up lines where both pitchers K 20% of the batters they face.  In this simplistic view, we will assume no double plays or HBP:

Pitcher A: 6 IP, 5 H, 2 BB, 5 Ks with 25 batters faced
Pitcher B: 4 IP, 8 H, 5 BB, 5 Ks with 25 batters faced

Obviously, you would much rather see your starter deliver the first line.  In this case, notice that both pitchers faced the same number of batters and finished with the same strikeout total.  Pitcher A delivers a solid K/9 of 7.5 while pitcher B posts an impressive 11.25 K/9.  These things tend to happen in the short run, but over the course of a season, relatively inefficient pitchers like Francisco Liriano and Tim Lincecum are going to post higher K/9 ratios than comparable pitchers who face fewer batters per inning.

The Curious Case of Max Scherzer

Let’s consider the case of Max Scherzer for a moment.  Over the last three seasons, Scherzer has posted K/9s of 11.08, 10.08, and 10.29.  Steamer projections for Scherzer in 2015 show an expected K/9 of 10.44 which seems perfectly reasonable without delving any deeper.

Just looking at K/9, we would assume that Scherzer was a better strikeout pitcher in 2014 than he was in 2013, right?  If we did, we would be wrong.  Scherzer struck out 28.7% of the batters he faced in 2013 and just 27.9% in 2014.  The difference is that Scherzer faced an average 4.10 batters per inning this season, compared to just 3.90 in 2013.  He issued a few more free passes in 2014, but he also had a BABIP increase from .259 to .315. In other words, because Scherzer allowed a few more hits, his K/9 makes it look like he is improving, when he is really trending down in the K category.

Now 30 years old, Max Scherzer has seen his fastball velocity drop for 3 consecutive years with a corresponding decline in swinging K rate and K percentage.  The only way Scherzer reaches his Steamer K/9 projection is if his ERA/WHIP numbers look more like they did in 2012.  If you end up owning Scherzer in 2015, you should be rooting for a K/9 under 10.00 and improved efficiency to go with it.  Unless he winds up in the NL, those K rate trends are highly unlikely to reverse themselves.

The Efficient Pitcher: Cueto vs. Liriano

Obviously, we all know who the superior pitcher is in terms of fantasy value, but lets take a look at just how much of an impact efficiency can have on a pitcher’s K/9.

In 2014, Johnny Cueto struck out 25.2% of the batters he faced. Liriano K’d a nearly identical 25.3%.  Cueto was one of the most efficient out-makers in all of baseball and finished the season with a WHIP of .96.  His ability to initiate weak contact and allow his premier defense to make plays surely contributed to his outstanding WHIP total.  Liriano, on the other hand, really struggled with his command at times and walked 4.49 batters per nine.  As a result, his WHIP was 1.30.

Because of these differences, Cueto faced an average of 3.95 batters per inning pitched, while Liriano faced 4.25.  While Cueto’s K/9 was an impressive 8.94, Liriano’s was a near elite 9.70.  Between the two, Liriano was not far superior strikeout pitcher, but the K/9 would lead us to believe that he was.

How to Use this Information

I could provide examples all day long, but let’s talk about application.  The trick here is not to be blinded by a large K/9 number when you are analyzing pitchers.  It is vitally important to look under the hood and figure out why their overall numbers look the way they do.  Too often, fantasy owners overrate inefficient pitchers like Liriano and Lincecum while overlooking players who will deliver more helpful overall lines.

Here are a few stats to focus on:

  • K/BB – Perhaps no stat will tell you more about a pitcher’s efficiency. I will almost never roster a pitcher with a K/BB under 3.00.
  • K% – This will help you put the pitcher’s K/9 into context. I try to avoid pitchers with K% under 20% in K/9 leagues.
  • Batted Ball Data – I am lumping these together, but you have to look at BABIP along with the batted ball breakdowns. When you see how many line drives, ground balls and fly balls a pitcher allows alongside career averages, you can make an educated guess as to whether or not his BABIP was flukey.
  • Swinging Strike% – Comparing swinging strike data with seasons past will help identify whether or not a pitcher is trending down in the K category.
  • R/L Splits – A large split difference could be a red flag. Pitchers who struggle to get either righties or lefties out, tend to be inconsistent.
  • xFIP – My favorite ERA indicator, xFIP calculates expected ERA given average MLB defense and an average HR/FB rate of 10.5%.

I am always going to avoid the “WHIP whales” in category leagues, because frankly there are better ways to get the Ks that you need.  I always like to build my staff around two aces who are able to efficiently contribute better than a strikeout per inning.  You don’t need to reach for Kershaw to get this done.  Guys like David Price and Zach Greinke will work just fine as your top two.

The real key, however, is how you build the rest of your staff.  Avoiding low K pitchers is important, but you should also try to grab a couple bullpen arms with K%s over 30.  The best way to make up for an Iwakuma type pitcher on your staff is to pair him with a bullpen strikeout artist.  I usually won’t draft closers like Jonathan Papelbon because his K rate is not going to be helpful enough.

Mid to Late Round Starters to Target

I am keeping a close eye on all of these pitchers.  Each of them have the potential to offer above average strikeout rates along with high-efficiency.

Carlos Carrasco, Cleveland Indians

I expect Carrasco to shoot up draft boards and be a trendy mid-round selection next season.  He has always had the talent, but since he started relying more on his electric slider, the Ks have started to come in bunches (26.5%).  His 2014 K/BB rate of 4.83 was elite. Carrasco enjoyed a 4% increase in his swinging strike rate from 2013 to 2014 and should be able to get about a strikeout an inning as a full-time starter.  The BABIP is likely to increase along with a slight bump in his BB rate, but there is still plenty here for fantasy owners to love.  Overall, I think an ERA near 3.00 and a WHIP under 1.15 is likely, so owners can still turn a nice profit with a 10th round investment.

Jacob deGrom, New York Mets

deGrom will likely be drafted around the same time as Carrasco next year.  His ratio stats were not quite as dominant, but I think they are more in line with what owners should look for in 2015. deGrom’s 25.5%K rate was very unexpected, but seems to be supported by an impressive 11.7 swinging strike percentage.  He has always done a nice job limiting walks, and may even be able to improve further in 2015.  He is a good bet to post a K/BB rate over 3.00, even if his K rate dips some.  Degrom’s ERA is going to be higher next season, but he is still capable of producing an ERA in the low 3s with a WHIP under 1.20 and a healthy K total. He is a solid option, but does not have as high a ceiling as Carrasco.

Matt Shoemaker, Los Angeles Angels

Shoemaker totally came out of nowhere last season, but anyone capable of posting a K/BB ratio of 5.17 is likely to post strong overall numbers.  Shoemaker’s second half was especially impressive as he maintained an ERA of 1.87 after the all-star break.  Clearly, he is not that good, but with a K% in the low twenties and a BB/9 under 2.00, Shoemaker should continue to produce useful numbers at a discount cost.  Expect an ERA in the low to mid threes with a solid WHIP and somewhere in the neighborhood of 8 K/9.

Michael Pineda, New York Yankees

Pineda is a bona fide ace if he can stay healthy, but injury risk makes his draft day price affordable.  Pineda only struck out 20.3 percent of the batters he faced, but an 11.2% swinging strike rate indicates that he is capable of more.  Amazingly, despite a relatively low 6.96 K/9, Pineda still had an 8.43 K/BB thanks to his impeccable command.  He is not likely to duplicate his .233 BABIP, but Pineda is always going to be an asset in the WHIP category because of his ability to limit walks.  At the end of the day, his value will hinge on his ability to stay healthy and to avoid HRs.

Mike Fiers, Milwaukee Brewers

I can’t really explain why Fiers had such a huge K rate spike in 2014.  He is a righty who tops out around 90 MPH and only has a swinging strike percentage of 9.5%.  Still, his deceptive delivery somehow allowed him to amass a 27.7% K rate and a K/9 of 9.54.  After striking out 11.35% of the batters he faced over 102 AAA innings, this insane K rate might not be a total fluke.  There is no chance that Fiers enjoys a full season BABIP of .224, but given his ability to generate Ks and limit walks, Fiers could make a solid value if other drafters sleep on him.  I would not consider him as anything more than an SP 5 or 6, but don’t be afraid to roll the dice if he falls too far.

Yusmeiro Petit, San Francisco Giants

Petit’s overall ratio numbers look excellent, but his ERA as a starter could scare some drafters away.  Don’t let it.  Petit is a great late round sleeper target if he wins a rotation spot.  Petit’s impressive K/BB rate of 6.05 will surely fall some if he is in the rotation for a full season, but he is still capable of generating a strikeout an inning as a starter.  Petit managed a K rate of 26.9% as a starter last season.  He is a fly ball pitcher who allows very few walks, so he is going to help the WHIP category.  HRs are always an issue for Petit, but he has the upside to be a serious value pick at the end of your draft.

Tommy Landseadel

Written by 

Tommy is also known as tlance on the CBS and Sports Hoopla message boards. He has been playing fantasy baseball for 16 years in many different format types and looks forward to helping you with your fantasy baseball questions! You can now follow me on Twitter @tlandseadel

4 thoughts on “A Few Thoughts About K/9”

  1. Nice post–thanks for the informative take. Wondering if you’d add to the list for me–I’m in an NL keeper and those guys you mentioned are all spoken for. Can you think of a few more NL players who fit the mold? Thanks.

  2. Like this post a lot! K/9 is good, but K% is MUCH better at determining pitcher’s worth in strikeouts. That being said, in looking at later rounds or for streamers, K/9 is valuable, because you are expecting less. If I can stream Liriano and get a K/9 of 9+ over 5 innings, I’m okay with that, cause it has good value, but I’m not drafting him over Cueto. I don’t think K/9, nor ANY stat, on its own is the best way to evaluate. People should always look at several things, and Tommy, my man, you have laid out a good framework for pitchers. You will see the above mentioned statistics, plenty in Field of Streams (shamless plus).Not sure if I am being clear, but I AM agreeing with Tommy, just wish he’d stop telling my league members who read this, my sleeper targets, haha! Great work!

Comments are closed.