Billy Hamilton debuted late in 2013 amid much fanfare, not as an offensive force but as a menace on the basepaths. Armed with blinding speed, baseball fans couldn’t wait to see how many stolen bases he could rack up, and despite just 22 plate appearances in 2013, Hamilton still accumulated 13 steals. He then followed that up with four consecutive seasons with 56+ stolen bases, establishing himself as one of the most-feared runners in the game.
Last season, MLB and Baseball Savant debuted Sprint Speed, defined as a player’s speed measured in “feet per second in a player’s fastest one-second window.” Data was rolled out for the 2015 through 2017 seasons and Hamilton was at the top of the Sprint Speed leaderboard for most of the year.
However, Hamilton was not alone. The Twins’ Byron Buxton battled with Hamilton all year, trying to supplant him as the fastest player in the major leagues. After a back-and-forth battle, the season ended with Buxton just edging out Hamilton as both players recorded a Sprint Speed just over 30 ft/sec.
It’s early this season but at first glance, the competition might be over between the two center fielders. Check out this plot.
Dear god, Byron Buxton is even faster than before.
Except, well, he isn’t. You see, Statcast actually changed how it calculated “a player’s fastest one-second window” this past offseason and they just announced the changes last week. A big reason the changes were prompted was due to Washington’s Trea Turner - also regarded as one of the fastest players in the majors - ranking 11th instead of being in the Top 5. This was probably due to how Sprint Speed was initially measured.
Last season, in order to get to plays where a runner was very likely to have been trying hard, we looked simply at non-homer plays where a player ran at least two bases (excluding being on second for an extra-base hit, since those are easy to jog home on). Sprint Speed looks at feet per second in a player’s fastest one-second window, and those plays are very likely to have a runner “trying” for at least one second.
We took the top 50 percent of those “qualified runs,” and we averaged them to get our seasonal average Sprint Speed. It was relatively simple, and it worked well for an initial rollout.
This season, the changes are described as:
So for 2018, a player’s seasonal Sprint Speed now includes home-to-first times, drawn only from balls defined as “topped” or “weakly hit,” because those are the types of plays likely to require serious effort from the runner. For those, based on the story the data told, we’re taking the average of the top 70 percent. (There’s also a minor regression built in, explained in more detail here.)
Thus, these changes introduced more opportunities for runners to show off their blazing speed (or lack thereof), especially those in which the player was sprinting his fastest. That is why Buxton appears to have gained four-tenths of a foot per second and is now running at an average of 30.5 ft/s (~20.8 MPH) compared to last year’s 30.1 ft/s. Plenty of other players have seen changes, both positive and negative. Last season, if I recall correctly Albert Pujols was supposedly the slowest runner at about 23 ft/s (~15.7 MPH). However, the updates have “slowed” Pujols’ speed from 2017 down to 21.8 ft/s (~14.9 MPH) and Brian McCann is currently this year’s Turtle of the Year at 21.6 ft/s (~14.7 MPH).
Regardless, this data should be even more accurate than it was in past years and it fascinates me to have concrete numbers assigned to the players in the major leagues. Toss in that we can now measure catchers’ arm strength and I’m excited to see the other data MLB and Statcast rolls out in the near future.