It is one thing for a pitcher to accrue a staggering number of strikeouts, but it is even more impressive when a pitcher has high strikeout numbers to go along with low walk numbers. Thank goodness, because a statistic measures exactly that!
Strikeout minus walk rate, also written as K-BB%, offers fantasy managers a way to identify pitchers who are striking out a ton of batters while also limiting walks.
These types of pitchers typically command and locate the ball well or induce swings and misses at a high rate. Here is a look at three of the best pitchers in terms of K-BB%.
Aaron Nola (SP – PHI): 25.6% K-BB rate
Aaron Nola has the third-highest K-BB%, behind only Shane McClanahan and Corbin Burnes, and a large reason for his success is a 3.2% walk rate, second in baseball.
Nola has also benefitted from a top-three called strike rate (CStr%) and a top-five called plus swinging-strike rate (CSW%), which have helped prop up his 10.0 K/9 rate.
The veteran righty has done well to limit walks, as Nola has the second-best BB/9 rate in the league at 1.10 walks per nine innings (which is also the best of his career). This has been a key to his success this year, although his ability to induce strikeouts and limit walks has not been reflected in his 3.42 ERA.
| Name | Team | K/9 | BB/9 | K/BB | K% | BB% | K-BB% | ERA | xFIP | SIERA |
| Shane McClanahan | TB | 12.19 | 1.62 | 7.54 | 35.50% | 4.70% | 30.80% | 1.87 | 2.02 | 2.21 |
| Corbin Burnes | MIL | 11.39 | 2.11 | 5.41 | 31.80% | 5.90% | 26.00% | 2.48 | 2.76 | 2.73 |
| Aaron Nola | PHI | 10.03 | 1.1 | 9.1 | 28.70% | 3.20% | 25.60% | 3.42 | 2.91 | 2.77 |
Fortunately for Nola, advanced ERA metrics like xFIP and SIERA suggest that his ERA should be closer to 2.70-2.90. Of the qualified pitchers in the top 10 for K-BB%, Nola is one of three that possess a lower xFIP and SIERA than their actual ERA.
The fact that he has a high K-BB% and advanced ERA metrics below his ERA should be a sign that good things are coming for Nola.
Gerrit Cole (SP – NYY): 24.5% K-BB rate
Gerrit Cole is another pitcher who is top 10 in K-BB rate and has a lower xFIP and SIERA than his ERA. Cole’s 24.5% K-BB rate is good for fourth among qualified starting pitchers.
| Name | Team | K/9 | BB/9 | K/BB | K% | BB% | K-BB% | ERA | xFIP | SIERA |
| Gerrit Cole | NYY | 11.28 | 2.28 | 4.94 | 30.70% | 6.20% | 24.50% | 3.63 | 2.79 | 2.88 |
| Zack Wheeler | PHI | 10.66 | 2.13 | 5 | 29.20% | 5.80% | 23.30% | 2.84 | 2.87 | 2.93 |
| Tarik Skubal | DET | 9.69 | 1.55 | 6.25 | 27.60% | 4.40% | 23.20% | 2.71 | 2.84 | 2.95 |
A major part of Cole’s top-five K/9 rate is due to his ability to induce swinging strikes. He has the fifth-highest swinging strike rate at 15.2% thanks to an arsenal that includes five pitches with whiff rates above 30%.
While Cole has been good, but not great, at limiting walks — his 6.2% walk rate is the same as Alex Wood’s — he has been exceptional at striking batters out. Similar to Nola, these impressive numbers have not been reflected in his season ERA, which sits at 3.63.
Managers who are disappointed with Cole after likely drafting him as their top pitcher should not worry. His 17.7% HR/FB rate is well above both his career average and the league average, and as that comes back down to earth, his ERA should improve as long as he continues to strike out batters and limit walks at his current rate.
Nathan Eovaldi (SP – BOS): 22.2% K-BB rate
The third pitcher in the top 10 of K-BB% whose xFIP and SIERA are lower than his ERA is Nathan Eovaldi. His 22.2% K-BB rate is 10th among qualified pitchers.
Eovaldi does not have the greatest strikeout numbers. In fact, he is outside the top 10 in K%, K/9, SwStr%, CStr% and CSW%. However, he is top three in walk rate at 3.6%. In 2021, he had a league-best walk rate at 4.6% and would have had the top walk rate in 2020 had he thrown 12 more innings to qualify.
| Name | Team | K/9 | BB/9 | K/BB | K% | BB% | K-BB% | ERA | xFIP | SIERA |
| Nestor Cortes | NYY | 9.93 | 1.96 | 5.07 | 28.60% | 5.60% | 23.00% | 1.96 | 3.24 | 3.1 |
| Luis Severino | NYY | 10.48 | 2.21 | 4.73 | 28.90% | 6.10% | 22.80% | 2.8 | 3.18 | 3.08 |
| Nathan Eovaldi | BOS | 9.48 | 1.32 | 7.2 | 25.80% | 3.60% | 22.20% | 3.16 | 3.09 | 3.11 |
While the righty has been very good this year overall and has been incredible at avoiding walks, he has been extremely unlucky in terms of home runs allowed. His HR/FB rate of 21.6% is nearly double his career average and the league average, suggesting that there should be some positive regression in the number of home runs he allows and his ERA.
This is largely why his xFIP and SIERA are both below his ERA, and why fantasy managers should continue to trust him throughout the rest of the season.
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