The intentional walk is dying, nearly dead, and the Astros are doing their part to kill it.

Last year, Houston set the record (at least since 1955, when records were first kept, so this is probably true all-time as well) for fewest intentional walks, issuing only four all season long. That seems like a monumental excess compared to what they're doing this year: Zero. Every other team has done it at least three times. The Marlins have done it 32 times. The Astros? Not once.

Their last intentional walk came nearly a full year ago, last August 17, when manager A.J. Hinch waved Jed Lowrie to first so that Héctor Rondón could face Khris Davis instead. (Davis flew out, though the Astros would later lose in extra innings.) It might be the last one they ever allow, at least if Hinch has anything to say about it.

"There hasn't really been a situation where I've really wanted to intentionally walk someone," Hinch told MLB.com. "I thought about doing it with [Christian] Yelich, when we played the Brewers, because he's the best player in baseball right now. I think any time you're adding a baserunner to the mix, you're creating another situation that might not be to your advantage."

But this isn't just another way in which the Astros are zigging while everyone else is zagging. (Before you ask: it's worth noting that this isn't just about Houston's pitcher quality, because the Orioles, owners of a worst-in-Baltimore-history team 5.68 ERA, have the second-fewest intentional walks, only three. Probably not unrelated: Baltimore hired Mike Elias from Houston to be their general manager last November.)

Instead, they're merely the biggest outlier in a more general trend, which is that the intentional walk is quickly becoming little more than a memory. This year, we're seeing just 0.17 intentional walks per game, or one every approximately six games. That breaks the record of 0.19, which was set in 2016 and 2018, and 0.20, which was set in 2014, '15, and '17, and, well, you get the point.

To put that in easier-to-understand terms, we're on pace for only about 820 intentional walks this year. Ten years ago, that was nearly 1,200. Back in 1969, the first year of the divisional era -- when there were still only 24 teams -- there were 1,436 free passes. What that should make clear is that this isn't really related to the change to no-pitch intentional walks, put in place prior to 2018. This is about teams deciding it no longer makes sense.

"I just don't believe in creating more opportunities for other things to happen," Hinch added. "Let's say if there's second and third, and everybody wants to walk the bases loaded, and then the unintentional walk after the intentional walk scores a run, or a hit-by-pitch now is in play, or … the match-up has to be perfect. I don't have numbers on this, but they don't seem to work out near as often as people want them to."

It's fun to note that a team has intentionally walked two or more batters 49 times this year and that 34 of them have lost -- including all eight times a team has given three free passes -- though it's not exactly conclusive, because teams already allowing traffic on the bases are more likely to find themselves in intentional-walk situations anyway. It's because while Hinch may not have had the numbers handy, we do.

Let's cherry-pick the scenario Hinch stated -- second and third base, presumably with one out in order to set up the double play. Between 2010-15, the Majors scored, on average, 1.4 runs in that situation. Add a free runner to make it bases loaded with one out, and that went _up_ to 1.5 runs.

Let's go deeper, based on that 2019 data, choosing a few of the most common situations in which you'd see an intentional walk.

• With one out and a runner on second, a walk increases the expected runs from 0.71 to 0.98.

• With two outs and a runner on second, a walk increases the expected runs from 0.34 to 0.47.

• With one out and runners on first and third, a walk increases the expected runs from 1.22 to 1.63.

• With two outs and runners on first and third, a walk increases the expected runs from 0.52 to 0.75.

• With one out and runners on second and third, a walk increases the expected runs from 1.37 to 1.63.

• With two outs and runners on second and third, a walk increases the expected runs from 0.62 to 0.75.

• With one out and a runner on third, a walk increases the expected runs from 0.95 to 1.22.

• With two outs and a runner on third, a walk increases the expected runs from 0.40 to 0.52.

Increases, increases, increases. Generally, you want fewer runners on, not more.

Now, that's all an oversimplification, because that's "on average," and certainly you'll be able to find examples where it worked. There are situations where, based on the identities of the current hitter and the next one, you'd still make the tradeoff. (Take the Pirates/Brewers game on June 30, when Pittsburgh, down 2-1 in the eighth, sensibly gave Yelich a free pass to load the bases ahead of the pitcher's spot. The pinch-hitter struck out. Of course, the first Brewers run had come in the fourth inning, when an intentional walk ahead of the pitcher led to Zach Davies knocking in an RBI single.)

But in those cases, the identities of the players involved had better be a big gain in order to overcome the hurt in average run expectancy, and that's exactly what we're seeing. That can also be shown in the fact that it's not just about the shrinking amount of intentional walks we're seeing, it's about where they're coming from.

If there's one place a free pass still makes some amount of sense, it's in front of the pitcher, given that pitchers batting routinely threaten all-time records for futility. (So far in 2019, pitchers are batting .128/.162/.165, the fourth-worst in modern history.) Obviously pinch-hitters factor in here, yet with the shortening of modern benches to squeeze in an endless number of relievers, we're seeing only about one pinch-hitter per game in the Majors.

This year, 27 percent of intentional walks have gone to number eight hitters, the highest since 1959, and well above the "since 1955" average of 19.5 percent. If we limit that to the National League only, the effect is even larger -- nearly 38 percent of intentional walks are to the eight hitter, well above the "since 1955" average of 24.2 percent, and a huge increase from just three years ago, when it was only 25.9 percent. (We haven't adjusted for non-interleague games, but the effect should be minimal.)

Interestingly, National League No. 8 hitters are on pace to receive approximately 200 intentional walks this year, which would be one of the six highest numbers on record. Putting a man on base to get to a real hitter is out. Putting one on base to get to a pitcher remains as popular as ever.

(Why? In part because the gap between No. 8 hitters and pitchers hitting has continued to grow over the years, and it's not just about pitchers being completely unable to hit. It's because even No. 8 hitters can mash the ball now. Put another way, this year, the gap between NL No. 8 hitters [.685 OPS] and pitchers hitting [.327] is 358 points. By comparison, back in 1971, when the share of free passes to NL No. 8 hitters was at its lowest, the gap between their .614 and the .382 of pitchers that year was only 232 points.)

So: why do the Marlins approach this so differently? In addition to issuing the most free passes this year, their 73 last year were the most, too, as were their 59 in 2017 and their 62 in 2016. Another way to say that is that since 2016, the Marlins have issued 226 intentional walks, more than five times as many as the 40 from Houston.

That doesn't seem like a coincidence either, because Miami actually had issued the eighth-fewest in 2015, their final season before hiring Don Mattingly as manager. They've offered the most intentional walks each year he's been in charge, though again, it's not just about pitcher quality, because the Marlins arms have been a lot better than you might think this year.

"The situation just tells you what to do," Mattingly said. "There's been a few of those where we've had open bases, and the count gets to the point where you're like, 'OK, the next guy is a better matchup.' You don't necessarily want to walk that guy, but you're also kind of pitching around him. If he doesn't chase into a good count, then you're like, 'Ok, just put him on, and go on to the next guy.'"

That's a good explanation -- intentional walk not as strategy, but only after someone else has gone awry -- except it hasn't actually played out that way. Just four of Miami's 32 free passes have come after a pitch has been thrown.

While it's true that -- Miami aside -- this is more of a general trend, we've seen some outliers in the past. Take the 1974 Dodgers, for example. If you were to look at the (pre-2019) leaderboards for fewest intentional walks offered, you'd find that the top 18 in full seasons all came in the 21st century ... except that the '74 Dodgers only issued nine, tied for fourth-fewest. (They held the record for decades, until the 2016 Royals issued just eight.)

Those 1974 Dodgers won 102 games and the National League pennant, thanks in part due to a best-in-the-National League 2.98 ERA, so perhaps Hall of Fame manager Walter Alston didn't feel much need to meddle. But it may also have been in part because that was the year that Mike Marshall won the National League Cy Young Award throwing 208 1/3 innings (!) over 106 games (!!) in relief, and, as reports of the time indicate, he wasn't having it.

“Twice this year, for example, Alston has requested an intentional walk," reported a Cincinnati paper at the time. "Twice Marshall has refused ... ‘I’ve never seen an intentional walk work,’ he explained.”

The previous year, Marshall had issued 12 free passes in 179 innings for the Expos -- though it should be noted that it did actually work 10 times. But since most intentional walks come in the late innings -- this year, there have been 173 in the seventh, eighth, and ninth, compared to just 160 in the first five innings -- a reliever who refused to do it could certainly skew the numbers.

(Meanwhile in 1974: the Padres issued a whopping 116 intentional walks, the most of any team on record, and Dodger shortstop Bill Russell received 25, the most in the league and nearly three times as many as his team handed out, despite hitting just .269/.336/.351. He, of course, batted 8th 90 times that season.)

The intentional walk will never disappear permanently, forever. There's always going to be the situation where you have an outstanding hitter coming to the plate and you'd do almost anything to get to the weaker one behind him, especially if double switches have put the pitcher in a middle-of-the-order spot. But like sacrifice bunts and the stolen base attempt, we're seeing fewer and fewer of them. The Astros, as they have in so many areas of the game, are leading the way.

MLB.com's David Adler and Joe Frisaro contributed to the reporting of this piece.