The 41–26 Diamondbacks have battled the Dodgers and Rockies to a near-standstill in the National League West thanks to a few obvious strengths. D-backs first baseman Paul Goldschmidt, who’s putting together a near-perfect facsimile of his 2015 MVP runner-up season, has been the best player in the National League. The starting rotation, led by Zack Greinke, Robbie Ray, Taijuan Walker, and Zack Godley (who’s picked up beyond where the injured Shelby Miller left off), leads the majors in WAR. Meanwhile, the bullpen, which was expected to be the team’s weakest link, ranks fifth in baseball in win probability added.

But Arizona has also stayed within one game of the West’s other top contenders courtesy of at least one nonobvious strength: by running the bases better than any other team in 2017. Looking at this season alone undersells them. Despite having traded Jean Segura, their leading base stealer from last season, the Diamondbacks, through more than 40 percent of their schedule, have run like the best baserunning team since the dead-ball era.

The D-backs don’t stand out among the stolen-base league leaders: They’re fifth in steals and third in net steals (steals minus times caught stealing). Their baserunning excellence is built on the back of proverbial “didn’t show up in the box score” plays. In the era of almost-total tracking of events on the field, though, those subtle contributions are no longer lost on those who weren’t watching.

Take a game against Pittsburgh on May 31, when the Diamondbacks fought the Pirates to a 5–5 tie through 13 innings. In the top of the 14th, David Peralta led off with a single and advanced to second on a Goldschmidt groundout, which was followed by a Jake Lamb walk. With Chris Owings up, Lamb took an enormous lead — 22 feet at the time the pitch was released, according to Statcast. As Lamb explored the lead-length limits, Pirates first baseman Josh Bell broke back to the bag to set up a back-pick attempt by catcher Elias Díaz.

But Díaz’s’s throw never came, because Owings poked a single through the hole Bell had just vacated, allowing Peralta to score the game-winning run.

Typically, Statcast says, a ball struck at that speed and angle is more likely than not to turn into an out, with a hit probability of only 43 percent. Thanks to Lamb’s lead and the defensive adjustment it forced, in this instance a single was all but assured.

“Had [Bell] stayed at his position, he would’ve fielded that ball and possibly turned it into a double play,” says Diamondbacks first-base and baserunning coach Dave McKay, pictured blurrily leaning Lamb’s way in the image above. “We didn’t steal any bases, but you had this big lead that forced them into making the mistake, and we ended up taking advantage of it. They know the whole deal, they know our guys will run. And if he doesn’t, and they’re actually trying to shorten up his lead by playing close to the bag, well, that’s kind of playing into our hands, too.”

Statcast can testify to the fact that Arizona’s runners have tested opponents all year. No team has averaged longer leads than the Diamondbacks’ 16 feet. According to FanGraphs’ baserunning metric, BsR — which takes into account not only stolen bases and caught stealings, but also a team’s ability to take extra bases on nonstealing plays, stay out of double plays, avoid other outs on the bases, and so on — the Diamondbacks have been 19.4 runs (roughly two wins) above average, with the bulk of that value coming from non-base-stealing plays. Through Wednesday’s games, only the Rangers ranked higher in Baseball-Reference’s extra bases taken percentage, but the Rangers had made 29 outs on the bases, fourth-most in the majors. The Diamondbacks had made only 12, second-best behind the Brewers — who are one of the worst teams at taking extra bases. Most teams have to choose between being ultra-aggressive in advancing and ultra-protective of their outs. Only the Diamondbacks have succeeded in being both.

MLB Advanced Media hasn’t yet publicly parsed Statcast to identify runners with the most efficient routes. But McKay believes that in addition to taking aggressive leads, the Diamondbacks are also the best corner-cutters in baseball, a compliment that might sound like an insult in any other context. McKay is a man who cares about corners: For him, the real story of the 2001 Jeter “flip” play wasn’t Jeter ranging far from his position or Jeremy Giambi’s decision not to slide, but Giambi’s wide turns around the bases, which McKay estimates made him run 12–15 feet farther than he had to.

The Diamondbacks’ corners are hospital-tight. We haven’t even reached the official start of the summer, but Arizona’s 19.4 BsR ranks 24th since 1920, roughly five runs behind the 2013 Mets, whose first-base coach Tom Goodwin turned baserunning into a team-wide competition. The D-backs probably have bigger dreams than overtaking the 2010 Rays on a semi-obscure sabermetric leaderboard, but those Rays’ record (an outlier at 37.6 runs) is within their grasp. Arizona’s BsR with half of June left to play is three runs ahead of where Tampa Bay’s stood at the end of the month.

McKay — a former big league infielder and, according to BsR, a slightly below-average base runner himself — is in his 34th season as a major league coach. He’s spent all but one of those seasons stationed at first base, starting with the A’s and later coaching for the Cardinals and Cubs before joining the Diamondbacks in 2014. In all of those seasons, he says, he’s never coached a team whose baserunning rivaled this one’s.

The Diamondbacks, who ranked second in BsR behind San Diego last season, have been above-average base runners in each of McKay’s seasons in Arizona, which has made them almost the mirror image of the station-to-station Tigers at the other end of the scale. The year before he was hired, their baserunning ranked last in the National League. Small wonder, then, that McKay has gotten good press in the past, and that he wasn’t one of the coaches dismissed late last year after new GM Mike Hazen and manager Torey Lovullo restructured their staff.

McKay’s experience has taught him that an extra foot of lead length, and an extra run, might matter. “People ask, ‘What’s the importance of one game?’” McKay says. “Well, I think back to 2006 and I think back to 2011. We in St. Louis won a World Championship, and we clinched on the last day of both those years. And so one more loss and you’re at home playing golf with everybody else.”

McKay knows that baserunning isn’t the separator that a great offense, defense, or pitching staff is, but he also believes that good base runners can be built much more easily. “[Unlike] hitting or fielding, it’s one area where you can work at it and you can be a real good base runner if you want to,” he says. “You just have to want it.” Not every team needs or wants it enough to try.

McKay isn’t such a baserunning savant that he can turn any team into a terror on the bases; that 2011 Cardinals club, in fact, had the second-worst BsR of that season. In the absence of elite speed, great baserunning requires a mind-set that some rosters seem to embrace much more readily than others. McKay acknowledges that “there’s a lot of standing around” in baseball, and a player at rest remains at rest unless reminded to move. The key to combating that impulse, he says, is convincing players “to program [their minds] to the fact that hey, every now and then I have to sprint.”

McKay attributes the effect he has as a coach to the power of positive reinforcement, sustained throughout the season. “If you just use spring training to talk about baserunning … and then you don’t talk about it anymore during the season, then they’ll slowly start to slip,” he says. “So it’s an everyday thing.”

That task entails keeping an eye out for moments even more easily missed than Lamb’s win-enabling lead, and then bringing them to players’ attention. “You tell a player today that, ‘Boy, you took a great turn going from first to third the other day,’ and then you watch them the next game and that turn gets even better because it’s in his mind. … And so you make that point. And I think that would go overlooked if you didn’t. And again, it just stresses to them the importance and the feel-good to know that, ‘You know what? Hey, I won the game. I won the game by going first to third in the fifth inning.’”

McKay says it takes time to talk non-speed demons into believing that baserunning pays, but four seasons into his tenure, attention to baserunning is at the core of the Diamondbacks’ culture. “They seem to really buy into it,” he says. “They really seem to be excited about what they can do on the bases.” These days, he doesn’t have to be as rah-rah about baserunning; repeat the refrain often enough, and the players “start policing each other. And at that point, you got something. And I think that’s what we have now. We have guys like Goldy.”

McKay compares Goldschmidt’s baserunning to that of peak Albert Pujols. Like Pujols, Goldschmidt is too good a hitter for baserunning to make or break his career, but he wants to be the best at it anyway, which sets a valuable example for players who aren’t nearly as close to perfection at the plate. His 13 steals lead the Diamondbacks, and his 6.0 BsR ranks third in the majors, barely behind Billy Hamilton and Xander Bogaerts. Goldschmidt’s BsR places him in the top 10 in baseball since the Diamondbacks hired McKay; to find the next first full-time first baseman on the list, you have to scroll down to 114th.

Goldschmidt has always been a long-lead guy who cares about baserunning, but his technique is improving with time. “I think that’s probably a thing that helped Goldy the most [with] getting jumps and stealing bases was he felt uncomfortable about getting a lead and getting picked off,” McKay says. “And so we spent time with these guys on how to get back to first base.” Goldschmidt, who ranks eighth in the majors with 66 steals since the start of 2015, has set career-highs in steals in each of the past two seasons, and he has a chance to extend the streak this year. “There are several guys on our team faster than Goldy,” McKay says. “But Goldy is very smart. He really, really does his homework … and if you slip, you give him a chance, and then he’ll steal the base.”

McKay has been coaching first base since before sabermetrics started making major inroads into the game, but his job isn’t so different today. While he relies on the information he’s given to position Arizona’s outfielders, baserunning, he says, is still largely a non-data-driven art. “I can go and get some information on this pitcher’s times to the plate, but then I have to see it for myself,” he says. “Or the pitcher’s move, the fact that he’s got a good move or whatever, I have to see it for myself, and then the players have to see it for themselves.”

But even if stats aren’t responsible for the Diamondbacks’ baserunning excellence, they have, at least, allowed us to spot it. Arizona’s running will likely be worth a few wins, and with the way the West is going, one of those wins could count.

Thanks to Mike Petriello of MLBAM for research assistance.