Category Archives: Statcast

THT: The Lurking Error in Statcast Pitch Data

Today at The Hardball Times, I wrote about pitch-tracking differences between PITCHf/x and Statcast. I found that Statcast’s radar is worse at tracking vertical movement and vertical location, but has similar ability for horizontal movement and horizontal location. And velocities are more accurate since Trackman’s out-of-the-hand readings replaced PITCHf/x’s 50-foot recordings. In addition to the general takeaways, there are interesting differences from park to park. You can read more here.


FG: The Drop in Yoenis Cespedes’ Launch Angle

On Friday, my latest post for FanGraphs covered the detrimental changes to Yoenis Cespedes’ launch angle. The analysis recommends a more appropriate center angle for Cespedes and reveals that his swing plane wasn’t optimal in 2015 and 2016.

Route Efficiency and Wind

Despite playing a shallow center field, Juan Lagares almost never allows batted balls to go over his head.  This drive from Atlanta’s Jace Peterson seemed like one that would actually land untouched in the warning track, due to its high hit velocity (99 mph) and the windy conditions at Citi Field this past Wednesday.  And yet, it beget another terrific play to add to Lagares’ growing highlight reel.

Ahead of last night’s Mets-Yankees game, MLB Network ran a short segment in which Statcast data was used to compare Lagares’ play with the home-run-stealing grabs by Kevin Pillar and George Springer from a few days ago.  Here’s a screenshot of their graphic:


Notice the “route efficiency” figure below the measurement of each fielder’s total distance covered.’s Matthew Leach describes route efficiency as such:

It’s a measure of the shortest point-to-point distance between where the player starts and where he ends, relative to how far he actually traveled.

So a player who takes a perfect straight-line path in his fielding effort registers a 100% efficiency rating.  A player who struggles to get a beat on the ball and drifts will earn a decreased rating.  This is a proxy for a player’s judgment in the field.  Obviously, that’s hugely useful for defensive evaluation, but this approach is still deceptive.

Lagares is docked ~4 percentage points in route efficiency for changing direction twice, implying that his route to the ball was suboptimal.  But keep in mind that the conditions at Citi Field were blustery that night, with strong, swirling winds.  In the face of those gusts, a batted ball’s projected landing spot will fluctuate throughout its flight.  Neither Springer nor Pillar dealt with comparable wind conditions (and to boot, Pillar was playing with Rogers Centre’s roof closed).  There’s context that “route efficiency” isn’t accounting for.

A more accurate version of route efficiency would be calculated on a continuous basis in order to see how well the outfielder adjusted his route depending on changes in Statcast’s projected landing spot for a given batted ball.  Until that’s done, it’s misleading to directly compare players’ route efficiency and dock those whose zig-zagging routes actually may have been appropriate for specific plays.