There was a play in the midst of the wackiness of Game 5 of the National League Division Series presented by T-Mobile that's almost certainly going to be lost to history. After all, it came in the midst of aces struggling in relief, a dropped third strike that led to a run after an errant throw, and however it was that you'd describe the entire fifth inning. What will be lost in the Cubs' dramatic victory to advance to the NL Championship Series presented by Camping World will be Daniel Murphy's sixth-inning double, because from the outside, it looked straightforward.
Murphy doubled to left, advancing Ryan Zimmerman from first to third while scoring Bryce Harper to close the Cubs' lead to 8-6 with two outs in the inning. Simple, right? Murphy doubled 43 times this year, seventh most in baseball. He does this a lot, and he looked pretty happy about this one.
But there was something about this one that stood out. Why didn't Zimmerman try to score, too? And might he have been safe if he had? Zimmerman scored from first on a double six times this year, and it's not an unimportant question. Since Anthony Rendon was walked and Matt Wieters flied out, Zimmerman never did make it home. The Nats would lose, 9-8. One run was everything.
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Let's start from the start, with Cubs lefty Mike Montgomery. Entering as the fourth Chicago pitcher of the night, Montgomery threw 14 pitches to five batters. He allowed two doubles and two walks (one intentional), plus threw a wild pitch that allowed Jayson Werth to score. Objectively, Montgomery did not have a strong game.
But Montgomery did do one thing very well -- the kind of thing that's not reflected in the box score. He kept Zimmerman from getting any sort of lead at first. The Major League average lead distance at first base when the pitch is released is 14.8 feet; against lefties, it's a slightly smaller 14.2 ft. Still, it's just over 14 feet no matter who's on the mound, yet Zimmerman was standing just eight feet off the base when the ball left Montgomery's hand. Six feet may not sound like much, but it's going to be a big deal.

Murphy's blast to left cleared left fielder Benjamin Zobrist's head easily, but here the Cubs caught a break -- the ball hit the wall on a short hop and bounced back immediately to Zobrist. It took just 1.3 seconds after the ball hitting the ground for it to be in his glove; it took just a half-second after that for the throw to leave his hand, on its way to traveling 184 feet to the cutoff man. Zimmerman stayed at third, never advancing.
While Zimmerman isn't known for his speed, he's not exactly slow, either. Using Sprint Speed, which we define as a runner's feet per second in his fastest one-second window, we know that the average Major Leaguer's top speed is 27 feet per second, and that's exactly what Zimmerman's average is, too. He's as fast as Ian Kinsler or Joc Pederson, and on this play, he got a little extra, getting up to 27.8 feet per second at his fastest point.
It's that last part that's important, too. Where was Zimmerman's fastest window? Well, we can show you -- it was as he was approaching third. He made it from first to second in 4.19 seconds, despite having that eight-foot lead, but he made it from second to third in 4.04 seconds, even though it was a longer distance than the 82 feet he needed to go from first to second. Zimmerman was already at full speed.

So would a full-speed Zimmerman have been safe? We can estimate, based on what we know about how he runs. In May, Zimmerman scored from first on a Murphy double, with a nearly identical Sprint Speed of 28 feet per second, and a similar lead distance of 10.2 feet. Hitting full speed as he neared third, he got home in 3.45 seconds. We'll use that as an example.
In this case, Zimmerman reached third base almost at the same moment as shortstop Addison Russell received the cutoff throw, 169 feet from home plate. Let's compare this to a play from last year, when Russell received a cutoff throw from left fielder Chris Coghlan, who had tracked down a Stephen Piscotty double.
It's a great comparison, because in addition to it being the same shortstop, we have a situation that's more favorable to the runner. Russell was slightly farther into the field, 186 feet away from home rather than 169 feet. Runner Matt Carpenter was slightly slower than Zimmerman, with a Sprint Speed of 26.5 feet per second, and requiring 3.66 seconds to get from third to home; we're assuming Zimmerman is capable again of the 3.45 he showed in May. And not only that, but Carpenter also had a relatively unimpressive lead, just 9.5 feet.
When Russell received the ball, Carpenter had rounded third and was just 75 feet from home. But it took Russell just 2.4 seconds to deliver the throw, so Carpenter was out, easily. Given that on Thursday, Russell was closer, and that he can get the ball home from that distance in well under three seconds, it's pretty fair to say that Zimmerman would have been out at home with an on-target throw.

But remember, it didn't have to be that way. Zimmerman slowed as he approached third, knowing he wasn't going home. And due to the short lead, he was six feet behind an average runner to begin with. So this is less third-base coach Bob Henley making a too-conservative choice, and more about the short lead that Montgomery limited Zimmerman to in the first place, plus a nice play on Zobrist's part in getting the ball in. Looking back to the Carpenter play, if a faster runner had been closer to home while Russell was farther away from home, this might have been worth sending the runner.
If this all sounds familiar -- a controversial Washington baserunning decision at third base on a double to left field on a play involving Zimmerman in the sixth inning of a deciding NLDS Game 5 that the Nationals would lose by one run at home -- well, it ought to. Last season, a Zimmerman double led to Jayson Werth being thrown out by a mile in what would become a 4-3 loss to the Dodgers. Since shortstop Corey Seager was 34 feet closer than Russell, and Werth is slower than Zimmerman, with a 26.1 feet per second Sprint Speed on the play, it seemed like a clear mistake at the time, and it's easy to imagine the memory was fresh for Henley this time around. 

Of Murphy's 43 doubles this year, 16 came with a man on first base, and only seven of them didn't try to score. Obviously, there's a lot that goes into that decision, from speed to game situation to outfielder arm, but there's also this: At the time the ball was released, the average lead distance of the runners who tried to score was 15.3 feet. The average distance of the runners who did not try to score was just 12.9 feet, and at no point did a runner have a lead as short as Zimmerman's eight feet. Leads matter.
If Zimmerman had gone and been thrown out, then for the second year in a row, the third-base coach would have been roasted. But the choice on this play was made long before the runner got to third. It was made when Montgomery held him to a short lead in the first place. After all, the best way to get from one place to another quickly is to lessen the distance between those places. It was a very small thing, but it just may have helped the Cubs escape a wild night.