July 8, 2014
What is a Fast Runner Worth?
“He brings us that athletic dimension that we’ve been missing.”
“He’s can beat you in a bunch of different ways. That’s what we like about him.”
“He won’t clog up the bases.”
“He’s really fast.”
A confession: I reflexively recoil when I hear someone try to justify why someone is a good player by citing the fact that he’s fast. It’s not that I don’t get that speed on the basepaths has value to a team. In that weird part of the universe where everything else really is equal, I’d rather have a fast player than a slow one. The problem is that when I start hearing these arguments, it’s generally in the form of “Well, he’s not a very good hitter, but he’s fast. And his speed will cover for that fact that he’s not a good hitter.”
How much is speed worth anyway? Here at BP, we do have a baserunning metric (Base Running Runs, or BRR) that attempts to measure the additional runs that a player adds to a team by virtue of his performance on the basepaths above what we might expect from a league-average baserunner. For example, if a hitter goes from first to third on a single, he has “stolen” an extra base. Last year’s best baserunner by that metric was Matt Carpenter (seriously) checking in at 8.4 runs. (If you’re wondering how Carpenter, who’s no speed demon—seven career steals—won that title, it’s that he tended to be on base a lot when members of the Cardinals got hits, and he was adept at advancing.) If 8.4 runs is close to the upper limit, then why do people make such a big deal about speed? Sure, that’s nothing to sneeze at, but it’s also nothing to cough at.
It’s hard to study the effects of speed in isolation without knowing the rest of the context. A player could be an Olympic sprinter, but if he can’t get on base, what’s the point of his speed (other than as a pinch runner)? You can’t steal first base. Worse, there are plenty of players who survive in MLB basically because they are fast, despite their troubles as hitters. When we want to study the effect that fast players have on their team, we’re usually hamstrung by the fact that they are often subpar hitters, and that most certainly has an effect on the team’s overall output.
What if we could take a better hitter and plug in a Game Genie code that kept him the same hitter, but made him really fast. What would that do to a team?
Warning! Gory Mathematical Details Ahead!
I didn’t write the model to be 100 percent complete. For example, no one bunts in this world. There are no pinch hitters, the pitcher is always league average (as is the opposing defense), and the other team doesn’t bat, so there’s no chance to make strategic decisions based on the score. It’s not perfect, but it can answer the question, “Over nine innings of ‘normal’ baseball facing an average set of circumstances, how much would a lineup with X characteristics score over 162 games?”
For the purposes of this exercise, I created a lineup that was a composite of what came out of each lineup spot in 2013. That is, a composite of everything that was done (by a non-pitcher) in the leadoff spot, the second spot, the third spot, and on down the line. Most of the time, in the leadoff spot, teams have a regular leadoff hitter, but they’ll use some pinch hitters, and some injury replacements for a couple days, and some guys who were thrown into blowouts to give the leadoff hitter a few innings off. Overall, though, this is a good representation of the “average” leadoff hitter.
I set everyone’s speed to league average. I should mention that I’m using my own home-brewed speed scores. In this case, zero is league average. I then simulated 10,000 games for that lineup. After that (actually, concurrently with that), I simulated 10,000 games, now with the leadoff hitter having turbo speed (1.5 on my scale, which would put him in the range of Dee Gordon and Craig Gentry from last year). Then, 10,000 games with the no. 1 hitter returned to normal and the no. 2 hitter getting the magic pill. Then I made a magical team where everyone was super-fast and called it the 1985 St. Louis Cardinals. I had the computer keep track of how many runs each “team” scored in nine innings.
It looks as though adding speed to a player does more than does taking speed away. It’s actually nice to have a fast player, especially one who hits like a regular middle-of-the-order hitter. The effect was 18 runs—nearly two wins—for a no. 5 hitter. However, it also seems that adding speed all over the lineup doesn’t produce what the sum of the parts would suggest. There’s an upper limit to how much speed can influence the game. On the flip side, a team where everyone is slow actually suffers more than one might imagine based on the sum of its parts. One base-clogger might not be as much of a problem, but a whole team of them would be.
But here’s a question. How much of that spread between different spots in the batting order (the same upgrade produced very different results throughout the lineup) was because of the ability of a certain lineup spot to leverage speed versus a certain type of hitter to leverage speed? To look at that issue, I created a second set of simulations. I created a composite league-average hitter from 2013 (excluding pitchers hitting) and cloned him nine times over. This way, it’s always the same hitter over and over. Once again, I started with a baseline where everyone is also a league-average runner and then went through and ran a simulation in which each of the nine batting order positions was given the gift of speed. (Then, after that, each was given lead weights to walk around with.) Again, 10,000 games per simulation.
It looks like a good amount of the variation in outcomes can be explained by the fact that speed just plays better in some lineup positions than others…at least in our abstract world. It also looks like that the best place in the lineup for speed is not in the leadoff spot (where the manager usually sticks the fast guy), but in the second and third spots. It also looks like robbing this lineup of speed does little to affect outcomes. In some cases, the lineup does a little better.
Speed—Better Than a Keanu Reeves Movie!
But there are some takeaway lessons from this work. One is that standard practice of demanding that a leadoff hitter be fast (and sometimes having that be his only qualification) is actually not a good one. All else equal, speed actually plays better in the second spot in the lineup. Additionally, speed doesn’t seem to play as well at the bottom of the lineup. Now, that’s not to say that all fast guys should hit second. The loss of production at the plate that a team takes from having the fast guy hit second (and get more PAs) and having a better hitter who is slower hit down in the lineup might be bigger than the gain from getting the speed guy into an optimal place.
Say, however, that a manager has two players whom he plans to hit first and second. He considers them to be roughly equal to one another in their hitting prowess, but one is faster than the other. The manager should actually hit the fast guy second. There’s also the curious finding that adding speed affects a lineup more significantly than taking it away. In fact, inserting more speed and taking away speed appeared to have two entirely different effects on a lineup.
Finally, let’s remember that while some of these numbers per 162 games are gaudy, this represents the effect of a player suddenly waking up with truly elite speed (or with truly heavy weights tied to his legs). The nice thing about this model is that it can be re-programmed. For example, suppose that instead of a speed score of 1.5 on my scale, our hitter was only a (very respectable) 1.0. Would he still get all of the benefits? Just some? The major strength of the MCM approach is that it allows us to look (at least somewhat) at how the pieces of a lineup interact with one another (and they do!). Indeed, we saw that just changing the lineup spot of the fast runner (backed up by otherwise cloned hitters) made a big difference over the course of a year. Structure matters. It’s tempting to want to say “Smith is worth three wins a year, so plugging him into Team X’s lineup will make them three wins better.” We need to be a bit more careful than that.