Ahead of the 2017 season, Major League Baseball officially transitioned their pitch tracking away from the familiar Pitchf/x to the Statcast system. The former used only cameras to measure the velocity, position, and break of every pitch in real time, but the latter introduced radar to the mix as well.
According to FiveThirtyEight.com, the new Statcast system, which incorporates radar, is far more advanced and is theoretically an enormous improvement … when it works. Unfortunately, that hasn’t always been the case so far this year.
Early in the season, baseball fans were wowed – but confused – by data that showed pitchers like Madison Bumgarner throwing one, two, and even up to three miles per hour faster than their career averages (at the beginning of the season, no less). And in Chicago, Cubs fans were rightfully concerned when radar guns displayed readings that were all showing fastball velocities for all starters much lower than their historical averages.
At FiveThirtyEight.com, Rob Arthur pointed out that it wasn’t just the velocity readings that were off throughout baseball. In addition to unexpected pitch speed, unexpected differences in pitch break (the horizontal and vertical movement of pitches) has become increasingly apparent.
Making matters worse, in Arthur’s words, some ballparks featured much larger errors than others (the Braves’ SunTrust Park has been among the most accurate, while the Reds’ Great American Ball Park has been the least). So in other words, even our data inconsistencies are showing inconsistencies.
Because the pitch trackers at every stadium are calibrated independently, some may be off – in either direction – more so than others. Specifically, Arthur pointed out that the Cubs’ widely-discussed low velocities may not actually be a product of the coaching staff or front office easing off the gas, but could instead just be bad data.
Arthur briefly mentions evidence of non-Cubs pitchers losing velocity when they come to Wrigley, but doesn’t share any of the data or specifics. So I decided to look into it, and I was pretty shocked by what I found.
When comparing the fastball velocities (both four-seamers and two-seamers/sinkers) of the Cubs’ five starting pitchers, the data suggests something might simply be off with Wrigley Field’s pitch tracker:
Just about every type of fastball from every single Cubs starter has been notably “faster” when they’re throwing it somewhere other than Wrigley Field. Brett Anderson’s four-seamer is the only pitch that has been recorded at a higher velocity at Wrigley.*
According to the data, the Cubs rotations’ collective fastballs have been clocked somewhere between 0.86 MPH – 1.04 MPH faster at other stadiums (which also brings up another problem: how inaccurately calibrated are the guns at those stadiums?).
Before we go any further, I do want to point out that these are just five pitchers on the Cubs, most of whom have had just five starts. There is not a huge sample here. In addition, external factors like weather and time of year (pitchers typically throw slower in their first starts of the season than later starts), among many other things, cannot be properly smoothed out just yet. But still. This is not nothing. It’s actually very much something to keep an eye on.
At best, we very clearly need to take these significant data differences into consideration when analyzing the fastball velocities of any pitchers on the Cubs. At worst, virtually all of the velocity data for all MLB pitchers has been suspect to date.
Don’t get me wrong: all five of the Cubs starters could be throwing more slowly than usual, but the extent of that drop has now come very much into question. And it’s fair to wonder if it’s something we would have even noticed AT ALL had the readings been more consistent among the ballparks – especially for John Lackey’s four-seamer (+2.0 MPH), Kyle Hendricks’ four-seamer (+2.08 MPH), and Jake Arrieta’s sinker (+1.44 MPH).
Those are huge differences right there. So stay posted, because we’ll keep getting more and more data, including in Arrieta’s next start tonight at Wrigley Field.
*(You could explain this one away if you were so inclined. For one, Anderson’s first start back – on the road – featured far lower velocity readings across the board, which isn’t that atypical for any player, let alone one returning from a season-ending injury in 2016. For another, he’s thrown 36% fewer four-seamers than sinkers this season, so it’s not exactly a one-to-one ratio.)
Brett Taylor contributed to this post.