Speed Thrills: The D-backs on the base-paths in 2022

Fangraphs’ has a BsR stat, which measures the value of a team on the basepaths over the course of a season. It includes, “stolen bases, caught stealings, and other base running plays (taking extra bases, being thrown out on the bases, etc) into runs above and below average.” By this number, the Diamondbacks were the best base-running team in the major leagues this year, collectively being worth 25.4 BsR above average: nobody else was even at 20, with the next best being the Dodgers, at +19.9 BsR. It also represented a franchise record, beating the previous high of +18.3 BsR in 2019. I figured it might be interesting to dig into the reasons why the team has done so well this year.

Is it pure speed?

We obviously know that the team has its share of burners on the basepaths this year. First, there was Tim Locastro, who was the Fastest Man in Baseball over the past couple of seasons, though he was dealt to the Yankees at the deadline. However replacing him was someone who is perhaps even faster, in prospect Corbin Carroll. According to Stacast, he has taken over the mantle of Locastro, as the fastest player in baseball this season, with an average sprint speed of 30.7 mph, and capable of going from home to first in 4.05 seconds. The video above shows that speed in action, Carroll taking just 10.75 seconds to reach third-base. But overall, where does the team rank for speed?

To find the answer I had to do some fiddling, since Baseball Savant doesn’t allow you to group sprint speed by team. So I downloaded the data, and calculated a weighted average for each team, taking into account both speed and number of sprints. By that, the D-backs were, perhaps surprisingly, only the seventh fastest in the majors, with an average speed of 27.6 feet per second. The quickest were the Guardians at 28.3 ft/s. This is partly because they had more quick players, with eight averaging 28.4 ft/s or quicker, compared to the D-backs’ six. But they also got full seasons out them, all but one having 150+ springs. Arizona only had Alek Thomas there. Next year should see an uptick, with a full season of Carroll, etc.

Here’s a table listing the average sprint speed for all thirty teams, along with the BsR metric for 2022, and the weighted average age of their position players.

If we plot speed against Base-running Runs, we’ll find that there is a relationship: faster teams are generally better on the bases, which would make logical sense. The correlation between sprint speed and BsR is 0.541, which is fairly significant. The chart below plots sprint speed against BsR, with a trend line to help illustrate the correlation. [Should you care, the formula for the trend-line is BsR = 15.8 x speed - 430] The D-backs are actually one of the furthest from the trend-line, being the highest dot on the plot. They managed to over-perform their expected BsR by 19.3 runs (expected = 6.1, actual = 25.4).

I also wondered if speed was related to player age. Sprint speed likely begins to decline earlier than some other skills, probably peaking around the mid-twenties. There is a definite tendency for teams which skew older to have slower sprint speeds. The chart below plots team age for position players against average sprint speed. The correlation here was even greater at -0.685. The D-backs were actually slower than you might expect for their age, being the third-youngest set of position players, with only Cleveland and Pittsburgh younger in 2022. And two more radically different results from their youth movement it’s hard to imagine, with the Guardians winning thirty more games than the Pirates

If I had to guess one reason why the Diamondbacks have done better on the basepaths than you’d expect from their speed, I’d probably be inclined to point the finger at first-base coach Dave McKay. He has occupied that position with various clubs since 1984, and it’s hard to imagine any other team can match that wealth of experience, in terms of getting the most out of players. In an interview here in 2019, Stewart explained, “The thing I explain to the players is you don’t have to be base stealers to be a great baserunning team. You go hard, you take advantage of their mistakes, By going hard you create mistakes, and so we could be a very good baserunning team, stealing no bases. But if the opportunity is there we will take it.”

Finally, I thought we should highlight speed at the individual level on the D-backs. The chart below is everyone who had more than 10 qualifying sprints for the team this year, in descending order of speed. Unsurprisingly, Carroll is top, and it’s not even that close. But between him, Jake McCarthy and Alek Thomas, the team could have the fastest outfield in the major-leagues next year. But there are some surprises as well. Would you have had backup catcher Cooper Hummel faster than Nick Ahmed or Daulton Varsho? He was considered a left fielder, that being where he spent more time in 2022. But his speed of 28.8 ft/s would be tied for quickest among catchers this season.

It certainly stands in contrast to the team’s other catchers ,Carson Kelly and Jose Herrera, who both rank near the bottom. That’s not a surprise: 80% of catchers in the majors come in at below MLB average speed of 27 ft/s. Kelly’s 25.6 figure is not that much below the median figure of 26.0 ft/s. But I was also a little surprised to see Seth Beer is - again, by quite some margin - the slowest player on the team. Even among designated hitters, hardly the quickest position on the field, Beer ranks in the bottom 20% for sprint speed. It’s also interesting to see Josh Rojas in the middle of the pack for speed, but he easily led the team in stolen bases, being successful in 23 of 26 attempts. That’s “running smarter”, rather than faster.

But what do you think of the charts above? How important is speed, and how important is coaching to use it the correct way?