HOUSTON — The 2019 Astros were baseball’s first team to go an entire season without an intentional walk. You probably know this: It’s a good statistic, solid fodder for a fun fact, the kind of thing that’s perfect for filling empty space on a broadcast. And you probably know what it means: The famously data-driven club took the statistical wisdom that the intentional walk will often (but not always) offer more risk than reward, and they took it to the extreme. But it’s difficult to say what, exactly, led them there. After all, the team is known for the secrecy around its strategy almost as much as it’s known for the strategy itself. Skipper A.J. Hinch said his IBB-lessness was a “non-topic” when asked about it in August. It’s just what Houston was doing (or, rather, not doing).

This offered two reasonable potential explanations: The Astros had decided that there was no situation at all in which an intentional walk was justifiable, or they had decided that it may be justifiable in some situations, but they simply had not encountered one of those situations.

Game 2 of the World Series yielded confirmation on this. Houston had, in fact, decided that the intentional walk could be justifiable in some situations—and it finally encountered one of them. When do the 2019 Astros consider the IBB worth it? When Juan Soto is at the plate, they’re down by one run in the seventh inning, there are two outs with runners on second and third, and they’re trying to even up the World Series.

Ultimately, it backfired. The inning unraveled quickly; Soto scored, the two runners ahead of him scored, the two hitters behind him scored. The game was lost. But results don’t always equal process. The IBB was a reasonable move in theory. It introduced the potential of an easy out, and, of course, it meant Astros reliever Ryan Pressly would not have to pitch to Soto. By FanGraphs’ win expectancy, the walk lowered Houston’s chances of victory slightly (from 30% to 28.8%), but that’s a small drop, and the potential benefit to it seemed clear. So just what drove Hinch to make the call?

“I’ve watched Soto just like you have.”

The leftfielder has revealed himself as a positively unearthly talent in his first two seasons in MLB; in his first postseason, he’s dazzled, including a stellar Game 1 of the World Series. (And, if you haven’t heard, he’s still not old enough to legally drink, let alone rent a car.) This was what it took to get Houston to break a season-long IBB-less M.O.

“We see the downside of it. Clearly, I think there’s a lot of downside, given that I haven’t done it all year,” Hinch said. “But ironically, I thought it was our best chance to limit their scoring. And instead it poured gasoline on a fire that was already burning.”

It was the first time that potential upside overtook that downside. But it wasn’t the first time this year that Hinch had considered the upside of an IBB.

“We have Mike Trout in our division, and we faced Christian Yelich,” Hinch said. The Brewers slugger had been present before the game to receive the Hank Aaron Award. “He was in the building. So maybe that’s what talked me into it."

Of course, there’s an enormous difference between facing Trout or Yelich in the summer and facing anyone in the World Series; playing for a championship is fundamentally unlike playing for a win. The sense of scale is totally altered. But it’s still striking—Mike Trout, Christian Yelich, and 20-year-old Juan Soto in his first October.

It’s useful to zoom out to analyze this a little more. We don’t know anything about the Astros’ IBB tendencies in 2019, because, of course, there were none. But we do know about what they were like in the seasons prior:

Season Astros' IBBs (Rank in MLB) MLB's IBB/Game 2016 19 (25) 0.19 2017 17 (T28) 0.20 2018 4 (30) 0.19 2019 0 (30) 0.16

The Astros have been relatively IBB-averse for a while now. Their core staff has stayed the same (Hinch has been with the team since 2015, and GM Jeff Luhnow since 2012) and so, too, has the fact that they’ve been broadly successful on the field. So their downward shift in intentional walks cannot be attributed to a visible change in regime or direction. Instead, it seems reasonable to view it as a gradual arc—with the few intentional walks that the team did use in the last two years illuminating something about when they’re most likely to consider an IBB and, in turn, illuminating something about what made this one so exceptional.

A necessary caveat: Every situation is different. It would be impossible to replicate the exact nuances of every batter-pitcher match-up and game state and context. But we can still look at some of the broader pieces of information. Like, for instance, the inning:

4th 5th 6th 7th 8th 9th Extras 2017 Astros 1 IBB 2 IBBs 2 IBBs 4 IBBs 7 IBBs 1 IBB --- 2018 Astros --- --- --- --- 2 IBBs 1 IBB 1 IBB

It’s probably not shocking that most intentional walks occur later in games. The reward of potentially getting out of a jam is more likely to outrank the risk of adding a baserunner when a team is running out of room to work. (In 2019, across MLB, the eighth was the most popular inning for an IBB.) So when the Astros cut back for 2018, they limited themselves to intentional walks only after the eighth, with no exceptions.

Until Soto in the World Series, when they called for it in the seventh.

As for the scoreboard?

Down 5 Down 4 Down 3 Down 2 Down 1 Tied Up 1 2017 Astros 2 IBBs 1 IBB 1 IBB 2 IBBs 3 IBBs 3 IBBs 5 IBBs 2018 Astros --- --- --- --- --- 2 IBBs 2 IBBs

An intentional walk is most common when a game is tied and second-most common when a team is down by one run. (In 2019, there were more than twice as many IBBs called for when a team was down by one than when a team was up by one.) But the Astros veered away from this idea in 2018: They were only interested in trying it when they were tied or ahead. The IBB wasn’t worth it if they were already losing.

Until Soto in the World Series, when they called for it while down by one.

The base state?

Runner on second Runner on third Runners on second/third 2017 Astros 5 IBBs 4 IBBs 8 IBBs 2018 Astros 2 IBBs 1 IBBs 1 IBBs

It is, again, probably not shocking that most intentional walks occur with a runner on second and an open space at third. Yet the 2017 Astros were most likely to go for it with a situation that’s a little riskier—intentionally walking someone to load the bases. But in 2018, when they withdrew their intentional walks across the board, they withdrew the hardest on these.

Until Soto in the World Series, when they called for it with runners on second and third.

It’s worth reiterating that the single biggest factor here is the fact that it was the World Series. The weight of playing for a championship warps the shape of the game; starters are relievers, no one cares much about rest, anything goes if the team can earn a win. But the Astros’ IBB in Game 2 was still striking.

Here was a line that they had drawn for themselves all year. And here they were crossing it. The context of their past intentional walks only makes it all the more stunning: If the Astros were unlikely to call for an IBB, they were especially unlikely to call for one before the eighth inning, when they were losing, with runners on both second and third. Yet they did anyway.

As for Soto’s skipper, Dave Martinez: Was he surprised to watch his 20-year-old phenom become the first hitter to push the 2019 Astros into an IBB?

“No,” he laughed. “No.”