February 20, 2013 posted by Matthew Dewoskin

Stats You Should Know: Swinging Strike % Edition

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Mike Fiers, SP, Milwaukee Brewers

Fantasy GMs have struggled with evaluating pitchers since the dawn of this silly, little game. Trying to figure out why some pitchers succeed while others fail can result in a lot of misspent energy at the best of times. ERAs are capable of wild swings from year to year. WHIPs are capable of wild swings from year to year. Wins are more dependent on the team’s offense rather than the starting pitcher (see Harrison, Matt). So what does that leave us? Strikeouts. Strikeouts is the one stat that varies the least from year to year. Most pitchers are usually within a standard deviation or two of their career average K total.

Swinging strike percentage is fairly self explanatory. It’s the percentage of pitches that result in a swinging strike. Simply take the number of swinging strikes and divide that number by the total pitches thrown.

Swinging strike percentage can be a very useful tool when evaluating starting pitchers. It’s a stat to use to figure out if strikeout numbers are legit or total BS. Pitcher X is a solid bet to regress if he posts a K/9 higher than his career average, but posts a lower than average swinging strike percentage. Speaking of Pitcher X…

Milwaukee Brewers starter Mike Fiers has gained a lot of steam this off-season as a sleeper candidate. He posted a 9.52 K/9 in 127 2/3 innings last year. He struck out more than a batter per inning last year as a starter. Fantasy GMs tend to take notice when a 27-year old rookie has a partial season like that. The problem is that Fiers is unlikely to repeat those numbers in 2013. First, Fiers isn’t what one would call “overpowering.” The average velocity on his fastball was only 88.1 MPH last year. Second, his swinging strike percentage was only 8.3%. League average was 9.1% last year. Fiers doesn’t miss very many bats and it’s unlikely that he will continue to post the kind of strikeouts that fantasy GMs are sleeping on.

On the other hand a pitcher that posts a ridiculously high K/9 and a ridiculously high swinging strike percentage is where fantasy GMs should want to be. Miss more bats, pick up more K’s. Sometimes plate discipline metrics are pretty simple.

Jeff Samardzija was a 27-year old in his first full season as a starting pitcher. Samardzija had the 6th best swinging strike percentage among qualifying starters in 2012 while posting a 9.27 K/9 ratio. His 12.1% swinging strike percentage means he’s missing a lot of bats. This is case when the numbers match the stuff. Samardzija features the 95 MPH average fastball, an electric slider along with a splitter that is among the best in baseball. Samardzija’s K numbers are completely 1. legit and 2. repeatable as long as The Shark stays healthy.

With any statistic, there are always outliers.

Tim Lincecum’s 2012 season looks like an outlier in a lot of areas. Lincecum had a bad season by fantasy standards and real life standards last year. He posted a career high 4.35 BB/9. He posted a career high 5.18 ERA. He posted a career high 1.47 WHIP. He also posted his highest swinging strike percentage since 2008. He clearly lost a few ticks on the radar gun and he suffered through a brutal season that forced fantasy GMs to start “I Drafted Tim Lincecum” support groups. Fantasy GMs sent about 5,943,000 emails to fantasy pundits on whether or not they should cut Lincecum in May and move on. He murdered more fantasy teams than Maurice Jones-Drew and Rajon Rondo combined, but he was still capable of missing bats? Wait, should he still be missing bats if his skills had truly degraded? This is why Lincecum is shaping up as a sleeper for 2012. He had this brutal season, but he still managed to post a 9.19 K/9 and post the 10th best swinging strike percentage among qualifying starters. He can still miss bats and post the K numbers that fantasy GMs need to compete. He’s not for the squeamish, but he appeared to figure something out in the playoffs and seems to have reinvented himself during the off-season.

Ubaldo Jimenez also had a disappointing year, but still managed to post a 7.28 K/9. That’s…competent. It also came with a 4.84 BB/9 and a lot of other numbers too gross to mention. Ubaldo’s swinging strike percentage mirrored his velocity. Both were down. Ubaldo posted a 7.0% swinging strike percentage. That’s a career low by a wide margin. It seems like the days of Ubaldo posting a swinging strike percentage over 9.0% are long gone. His average fastball velocity clocked in at 92.5 MPH. That’s almost four MPH off of his 96.1 MPH in 2010. Ubaldo was a mess all year and signs aren’t pointing to him returning to form any time soon.

Swinging strike percentage needs to be taken into consideration when looking for strikeouts, especially in the late rounds. A higher than average swinging strike percentage can easily project to on field results. Pitchers who miss bats should be able to strike batters out and strikeouts are very helpful for pitchers in fantasy baseball. It’s a useful tool for evaluating K/9 numbers and can assist fantasy GMs separate what’s real from what’s a mirage.


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