So how bad could this new intentional walk rule get?

I wrote:

But if you don’t have to throw those pitches, if the downside of the intentional walk is removed, you’re going to see them a lot more

and DomP replied:

Sorry, but the downside of an intentional walk is something like 98% giving away a free baserunner

But I don't agree. I think the right strategy now is to intentionally walk guys a lot. I mean a whole lot. I mean on the order of half a dozen times a game. Because pitchers can't hit.

There are some pretty bad hitting pitchers out there. Jon Lester has a career batting average of .064. Bartolo has a career batting average of .091. To be fair, those guys spent most of their career in the AL. But there are lots of pitchers in the NL batting around .100, and the average is about .130. AL pitchers are even worse, with an average average of .085 and an OBP of .127. And there are some AL pitchers who just can't hit period. Jon Lester spent nine years in the AL without recording a single hit (although he did draw a walk... with the bases loaded, snerk). Now that he's with the Cubs he's... still a very bad hitter, although better than he was in the AL.

Let's look at the league-average run-scoring expectancy chart. This is the expected number of runs you will score in various situations. With two outs, the only situation where the run-scoring expectancy is worse than the chance of an average AL pitcher reaching base is with nobody on (9.8% vs. 12.7%). Even then it is actually pretty close. So if you are playing in an NL stadium, the right play is to start walking guys as soon as there are two outs, if you can reach the pitcher without loading the bases. Depending on the pitcher, even loading the bases is totally fine, especially in an interleague game. Especially do this early in the game, when they aren't going to pinch-hit for him. Or, next level, if it's in the middle of the game and you want to encourage them to pinch-hit because he's dominating your offense.

And I haven't even considered all the situations where the win probability is improved by walking guys to get to exactly the position player you want. Top-heavy lineups (like, say, ours last year after the Story and Reynolds injuries) are just never going to bat in the 9th inning. Now granted you see most intentional walks in the 9th inning anyway, but with CarGo on second, why just pass on Nolan to face Dahl with two on and two out? Why not walk him too and face Descalso or Hundley? It's free.

Now, I'll admit to two issues with my argument.

First, I am not factoring in the indirect cost of turning the lineup over. Facing the top of the lineup instead of the bottom next inning will improve the offense's chance of scoring then, even if the chances are worse now. But that's only even relevant if you're doing something that would (up until now) be considered insane, like walking the entire bottom half of the lineup to get to the pitcher.

Second, is that walking all these guys increases the chance of scoring multiple runs. Most of this post is based around the probability of scoring one run. But if the pitcher you walked half the team to get to does end up on base somehow, you end up with not only a run scored, but the bases loaded and the top of the order coming up. I would estimate that if you go by expected runs rather than the simple chance of scoring any runs, walking the bases loaded probably has a total expected number of runs of about 1.5 times as much as the single-run calculation shows. But managers decide on gambling a large potential win vs. a smaller, more likely one all the time, when they decide whether to play small ball or go for the big inning. (Some of that is from the tiny chance of the pitcher getting an extra-base hit, the chance of a multi-run fielding error, and the biggest component, the roughly 40% chance of the leadoff hitter reaching base too, as well as subsequent hitters reaching base).

Third, is that the guys at the bottom of the order are typically below-average hitters. In particular, you can expect that the average pitcher is an average-hitting pitcher, but the average #7 and #8 hitter is a below-league-average hitter. This, again, favors not going hog-wild with the intentional walks always, because in real circumstances your run expectancy is just a little less than the matrix shows. So in reality most of the time, you would want to save this for the case of the good-hitting position players and the lousy-hitting pitcher.

Still, I think the idea of just walking the #8 guy with two outs always and facing the pitcher instead is totally on the table now. Previously you would typically only do it late in the game, with two outs and runners in scoring position. And walking the #7 and #8 guy sometimes. And even the #6 guy once in a while.

But for me, the worst part is the very significant chance that nobody will care. I mean, when the NFL changed the extra point rule, I thought about how horrible it would be if a playoff berth were to be decided by a missed extra point, or even worse, if a playoff game were. And then those things happened. And nobody cared. And then I stopped watching football.