A year ago, I took our batted ball distance and HR/FB rate analysis to its final step. Armed with additional metrics from our in-house math ninja Jeff Zimmerman, I published an equation to predict a hitter’s home run per fly ball rate, which I cleverly dubbed xHR/FB. Unfortunately, the actual equation derived has been hidden behind the FG+ pay wall since. No longer.
Draft season is fast approaching. That means that draft strategy will once again be a hot topic, as fantasy enthusiasts argue the merits of one philosophy versus another. But one particular debate threatens to make my head explode every single year. That is the notion of making your draft selection based on “best player available” (BPA) versus “position scarcity” (PS). The decision makes no sense to me. This is why.
Yesterday, the Astros continued to alter their outfield, this time by signing Colby Rasmus to a one-year contract. I’m sure glad I’m not overseeing the Astros depth chart, because it has seemingly changed every day. Rasmus suddenly becomes the team’s starting center fielder, with the collection of Jake Marisnick, Robbie Grossman and Alex Presley likely fighting for reserve roles. Let’s begin with the park factors to determine whether this impacts Rasmus’ fantasy value at all.
Yesterday, I dove into the three xHR/FB rate components to explain what fueled Todd Frazier’s home run surge. Today, I’ll dissect Miguel Cabrera, who set a new career low HR/FB rate, as it dipped from a career high of 25.4% in 2013 to just 14.0% in 2014.
Over the last couple of weeks, I have talked a lot about a hitter’s batted ball distance and the additional components included in my xHR/FB rate formula. The cool thing about learning about these metrics is now it’s a bit easier to understand what drove a particular hitter’s power surge or what led to a decline in home run output. As I am in the middle of my hitter projections, I have stumbled upon players with some interesting trends.
Yesterday, I shared with you the leaders and laggards of one of the components of my xHR/FB ratio, average absolute angle. Today, I check in on the leaders and laggards of the other non-distance variable of my equation, the standard deviation of distance (SDD). The SDD is much more stable year to year than the average absolute angle, coming in a bit below batted ball distance with a 0.50 correlation.
So we learned that a hitter’s average absolute angle isn’t very stable from year to year, but that doesn’t make it any less interesting to dissect. What is this strange sounding metric you ask? Think of the field broken into equal segments, with center field at 0 and each side of the field a value increasing or decreasing from there. According to the definition at Baseball Heat Maps, -45 is the left field line and 45 is the right field line. Since I don’t care which line the ball is hit toward, I asked for the absolute value of the angle, and then the average of all those batted ball angles. So the higher the number, the more toward the lines the hitter’s batted balls were hit. And obviously since fence distances are closest down the lines, a higher absolute angle should yield more homers. Therefore, it follows that this variable has the highest coefficient in my xHR/FB rate regression equation.
Yesterday, I discussed the hitters who enjoyed the largest surges in batted ball distance compared to their 2013 campaigns. Today I take a look at the other side of the coin, the decliners. In the 114 player sample that lost at least 15 feet of distance in Chad Young’s study, the hitters gained back about a third of their lost distance in year three. So a distance loss is more permanent than a gain, but players generally bounce back toward their historical marks.
Because I love examining how far batters hit their fly balls and homers, I’m going to continue the hop through the leaderboard for more analytical fun. Two years ago, Chad Young found that it is very difficult for a batter to sustain a surge in batted ball distance. Between aging and good old regression to the mean, batters who gained 15+ feet in distance gave half of that back in year three. The sample used in the study was certainly small, but I doubt the conclusion would change much with a larger data set. With that in mind, here are your 2014 distance surgers of at least 15 feet.
I was pretty successful at developing an equation to estimate what a hitter’s HR/FB rate should be given his fly ball + home run distance, along with the average absolute angle and standard deviation of the distance of those batted balls. My formula resulted in an R-squared mark of 0.649, which seems pretty darn good to me, especially when it completely ignores park factors, which we know play a significant role. On Tuesday, I found that the year-to-year correlation of a pitcher’s batted ball distance is less than half that of a hitter’s. Then yesterday, I discovered there was some correlation between a pitcher’s batted ball distance and his HR/FB rate and ISO mark.
