BB/9 Improvers Through the Lens of F-Strike%

In past pitcher articles, I have focused on strikeout and ground ball inducing skills and ignored control, though that has not been intentional. A couple of weeks ago, Carson Cistulli found that there was a strong inverse relationship between a pitcher’s F-Strike% and BB/9. This makes intuitive sense since once we already know the pitcher has an 0-1 count on the batter, it is that much less likely he ends up walking him. To that end, I decided to compare where a pitcher ranked in F-Strike% with his ranking in BB/9 to determine whose walk rates might be in for improvement. As a reminder, only “qualified” pitchers were included. And for reference, the league average F-Strike% has been 58.9%, while the league average BB/9 has been 3.30.

Clayton Richard’s BB/9 is right at his career average, but his F-Strike% is at a career high. His Zone% is also well above the league average, so he looks like a pitcher who should clearly improve upon his walk rate assuming these two metrics remain at their current levels. If that happens and his strikeout rate rebounds somewhat, he should return to generating some value in NL-Only leagues.

Over the last three seasons, Chad Billingsley’s F-Strike% has remained in a narrow range between 58.9% and 59.7%. This is the first year it has jumped above 60.0%. This is a good sign for his control, however his SwStk% is at its worst mark since his 2006 debut, and well below league average and his Contact% is much higher than you would expect to see from a power pitcher. This may just be a small sample fluke, but it would not be a surprise to see his strikeout rate fall if these metrics do not improve soon. That would offset any possible control gains.

Though Mike Pelfrey’s F-Strike% is at its highest mark ever, his Zone% sits right where it always has. I know Carson’s quick study found a much weaker relationship between Zone% and BB/9, but maybe Pelfrey is simply pumping in first pitch strikes and then having a more difficult time finding the zone in subsequent pitches. He is the first pitcher on the list so far that I would not expect an improved BB/9 in the short term.

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There is some good news and some bad news for Mat Latos owners. The good news is that his F-Strike% is a tick higher than last year and 25th best in baseball. His SwStk% is still excellent, as well as his Contact%. The bad news is that his Zone% has dropped well below league average and his fastball velocity is down nearly 2.0 miles per hour below last season. With all these mixed signals, I really do not know whether to advise trying to acquire him in a trade or not. Of course, it always depends what you would have to give up, but lingering health concerns are an issue and it does not help when you are backed by a weak offense where wins will be tough to come by.

Max Scherzer is seemingly pitching fantastically, and his appearance on this list seems all the more reason to remain optimistic. His F-Strike% and Zone% in line with past seasons indicate his BB/9 should drop closer to his career average. However, his FB% has now risen for a third straight year and has reached extreme fly ball territory, his fastball velocity is down a bit and his SwStk% has dropped. At 6-0 and with an xFIP a full run above his ERA, Scherzer actually makes for a pretty strong sell high candidate.





Mike Podhorzer is the 2015 Fantasy Sports Writers Association Baseball Writer of the Year and three-time Tout Wars champion. He is the author of the eBook Projecting X 2.0: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. Follow Mike on X@MikePodhorzer and contact him via email.

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Jordan RosenblumFanGraphs Staff
14 years ago

How do we know that the high first strike percentage won’t regress for people who have higher bb/9? How do we know which one is more likely to regress towards the other?