Before I dive into the purpose of this article, I would first like to introduce myself. My name is Michael Simione, also known as @SPStreamer, and this is my first article over here at RotoBaller. For those who don’t know me, my favorite aspect of baseball is, without a doubt, pitching. Most of my articles will be about pitchers and if you have any questions please feel free to reach out. I feel very lucky to be a part of the RotoBaller team and am extremely excited to see what the future holds!

K-BB% is one of the best metrics to use during the season and to measure a pitcher's performance. Simply put, the best pitchers have a high K-BB% because they strike out batters at a high rate and walk them at a low rate. In order to understand K-BB%, you have to understand K% and BB%. Luckily, they are very easy to calculate as you just divide the pitcher's strikeouts or walks by the total number of plate appearances. The way you get K-BB% is by subtracting K% from BB% and you get your K-BB% total. In this article, we will look at five pitchers who have increased their K-BB%. The table below shows each pitcher's K%, BB%, and K-BB% dating back to the second half of 2018.

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Yu Darvish, Chicago Cubs

Yu Darvish had one of the biggest mid-season turn arounds in recent memory. In the first half of 2019, Darvish struggled with a 5.01 ERA, 5.31 FIP, and 14.8 K-BB%. But when the calendar turned to July he became a completely different pitcher, posting a 2.76 ERA, 2.83 FIP, and 35.6 K-BB%. There were a couple of factors as to how Darvish was able to do this and why it might be sustainable.

In the second half, Darvish had better command and control of his pitches. The first sign was his decrease in BB% as it went down from 11.70% to a whopping 2.20% (lowest of any pitcher in the second half). He did this by shortening his extension on his delivery, Darvish was trying to extend too far and it was resulting in a loss of control. For instance, when he made this mechanical change, his fastball’s ISO went from a .434 to .204 which shows a massive shift in control.

Darvish messed with his pitch mix quite a lot as he essentially throws five different pitches (four-seam fastball, sinker, changeup, slider, curve, cutter, and splitter), but he mainly changed the usage of his four-seam fastball and cutter. By lowering his fastball usage and upping his cutter usage, it resulted in Darvish having an overall lower wOBA (.320 vs .261) and Barrel% (8.6 vs 5.9).

With these changes, Yu Darvish finally became the pitcher we had all had hoped for. The main key to his success is his walk rate, as it has always been his Achilles heel (career 8.8 BB%). If Darvish keeps these changes heading into this season he could very well have a great 2020 campaign. With his current ADP of 66, there is plenty of room for value.

Lucas Giolito, Chicago White Sox

Lucas Giolito finally had the breakout season we were waiting for by pitching his way to a 3.41 ERA, 3.43 FIP, and 3.57 SIERA in 2019. He had one of the most rapid ascents of K-BB% from the second half of 2018 to the end of 2019. In the three halves of baseball, his K-BB% went from 10.30% to 20.60% and then to 29.10%. In the matter of a year and a half of baseball, it went up 18.80 percent! What is also impressive is his SwStr% also went from 9.6% in the second half of 2018 to 15.6% in the second half of 2019.

Giolito’s success stemmed from perseverance and velocity. The White Sox weren’t doing Giolito any favors, so he decided to get outside help, which was the best decision he ever made. He met up with his former high school pitching coach who changed his delivery and made it more efficient. Overall in 2018, his average fastball velocity sat at 92.8 MPH, but in 2019 it sat at an average of 94.6 MPH. The increased velocity completely morphed his fastball, as his walk rate went down and the pVAL went from -13.5 in 2018 to 20.5 in 2019.

With a now insane 12 MPH difference between his fastball and changeup, a domino effect happened as his changeup became a better pitch in 2019. Compared to 2018, his changeup had a better O-Swing%, SwStr%, BAA, and wRC+ against.

Giolito’s newfound fastball lead him to become one of the most improved starters in baseball by increasing his K% and lowering his BB%. It’s the heart and soul behind the dramatic turnaround from a 6.13 ERA in 2018 to a 3.41 ERA in 2019. Giolito’s current APD of 48 is right on par with where it should be and you should feel confident taking him as an SP2.

Luke Weaver, Arizona Diamondbacks

Luke Weaver was a popular bounce-back candidate in 2019 after his 2018 season let down (4.94 ERA and 4.20 K-BB%). After 12 starts in 2019, it seemed as if Luke Weaver was in full break out mode as he was dominating hitters leading him to a 2.94 ERA, 3.07 FIP, and a 21.30 K-BB%. Unfortunately, an injury to Luke Weaver’s pitching arm shortened his season.

The main force behind Weaver’s success was his change in pitch mix. In the second half of 2018, he featured a four-seam fastball, changeup, and curveball. The four-seam fastball and changeup were serviceable pitches but Weaver would pound the strike zone with his curveball and it posted terrible results. It let up a .294 batting average against with a .265 ISO, which means he had control but no command and hitters jumped all over it.

In the time he pitched in 2019 he decided to add a cutter to his pitch mix and lower his curveball and four-seam fastball usage. The cutter essentially replaced his curveball as his go-to pitch when it came to needing a strike, and it worked well. In 2019 the cutter posted a .263 batting average against with a .158 ISO. Adding this pitch was huge as it also improved his four-seam fastball, curveball, and changeup.

Between the second half of 2018 and his 2019 season, Weaver saw a dramatic rise in his K% and a slight drop in his BB%. When you see a dramatic difference in players K-BB% like this it always means good things are happening, especially when it was due to him adding a fourth pitch. His current ADP is at 194 and while some might be worried about his arm injury his price makes him well worth the buy.

Robbie Ray, Arizona Diamondbacks

Robbie Ray is one of the most fascinating pitchers in baseball. He has some of the best pitches in the game but when it comes to command and control he tends to struggle. Ray is one of the best strikeout pitchers in baseball as he had a K% of 31.4 in 2018 and 31.5 in 2019. To go with it, he also had an impressive SwStr% of 12.8 and 13.6. Unfortunately with those strikeout rates came a horrendous 13.3 and 11.2 BB%.

In 2019, Robbie Ray’s best month of baseball came in July, where he posted a 3.26 ERA and 28.0 K-BB%. That month was his lowest BB% in any month of the three halves we see in the table above. He noticeably upped his four-seam fastball usage to 50% which lowered his walk percentage to 7.2%. He seems to have the most control with his fastball as he pounded the zone 57.3% of the time with it in 2019. This might be the key to Ray dropping his walk percentage.

If Ray can continue to drop his walk rate and push his K-BB% up to around 28% he can become an elite pitcher in baseball. He maybe on his way because in the three halves we looked at above, it has dropped from 13.80% to 12.10% to 10.00%. Robbie Ray is currently going at pick 151 and he holds value at that spot, especially if you are looking for strikeouts.

Tyler Beede, San Francisco Giants

Tyler Beede is an interesting late-round pick in 2019. He has popped up recently because he is one of a handful of pitchers that had three pitches with a SwStr rate of 15.0% or higher (curveball, changeup, slider/cutter). This makes Beede very intriguing and even more so intriguing because of his increase in K-BB% between the first and second half of last year (7.30% to 16.40%).

Halfway through the season, Beede decided to add another pitch to his repertoire which, depending on the site, is classified as both a slider and a cutter. If you watch him throw this pitch, the confusion is understandable because at times it breaks diagonally like a slider while at times it has a late break across like a cutter. This pitch was monumental in Beede’s development as it hits all of the marks with a 35.8 O-Swing%, 38.0 Zone%, and 17.6 SwStr%. If that wasn’t enough to get you excited it also produced a .273 average against with a .345 BABIP, which means you can expect it to be even better next year.

With Beede’s new pitch, it’s no wonder he is becoming a popular sleeper pick for 2020. His current ADP of 373 will cost you nothing in drafts. Taking him as a late-round flier could benefit you greatly in the long run and be one of the reasons you win your fantasy league in 2020.

Conclusion

The best pitchers in baseball always have a high K-BB% and it is very important to scout out the pitchers that are creating more strikeouts while giving up fewer walks. While looking at K-BB% splits is important, make sure to do your due diligence and dive into a pitcher to see if there is a reasoning behind it. Look for velocity change, pitch mix change, or even a mechanical change. Thank you for reading and as always, feel free to reach out to me with any questions!