A Game Theory approach to ABS challenges

Have you been victimised by the White Sox hitters and their poor decisions on when to challenge balls and strikes? Have you got an irrational dislike of Quero and Romo’s ability behind the dish? If so this article may be for you.

We are going to explore what I will be calling “the Game Theory approach to challenges”.

Game theory provides a framework for predicting and analysing strategic behaviour whenever people’s choices affect one another’s outcomes. Normally this is a mix of maths, psychology and logic, where your decision A impacts your opponent’s decision B (and how you then react to decision B and so on). This isn’t therefore pure game theory, but I like calling it this… so I am sticking with it.

The need for the framework

Rank	Team	Overall Success	Batter Success	Pitcher/Catcher Success
30	Pittsburgh Pirates	43.2%	44.0%	42.5%
29	Cleveland Guardians	45.2%	39.1%	50.8%
28	Chicago White Sox	45.9%	46.8%	45.5%
27	San Francisco Giants	48.1%	46.7%	49.5%
26	Seattle Mariners	50.9%	43.0%	59.4%
25	Baltimore Orioles	50.9%	49.6%	52.4%
24	San Diego Padres	51.0%	43.8%	55.6%
23	Milwaukee Brewers	51.2%	46.3%	53.6%
22	Atlanta Braves	51.2%	37.2%	62.0%
21	New York Mets	52.3%	49.7%	55.5%

Data updated through Friday, July 31.

The current data shows we rank 18th in batter challenge success rate (46.8%), but our pitcher/catcher challenge success rate is 29th (45.5%), which drags us down to 28th overall.

A team wanting to win it all cannot be satisfied with being 28th best in anything.

Status Quo

Before making any changes, you need to try and understand what the current system is.

I do not work for the Chicago White Sox and therefore have a limited idea of the current system. What we can do is make educated guesses based on comments made by our coaches and by the data we have.

The White Sox are 19th in overturns. What this shows is they are challenging a lot given the poor success rate.

Will Venable has been asked about this, and he has said things like “We give them a heads-up on areas that might be good to challenge or not.”

There is clearly data that exists and some guidance in place.

The key quote is from Bench coach Walker McKinven when talking to James Fegan, where he summed up the approach to strategy as trying to “pick up the $5 bill on the ground” (rather than waiting for $10 later).

Although McKinven was not talking specifically about ABS, it alludes to what we are seeing with our eyes and the data. The players are empowered to make decisions and that the number of successes is prioritised over success rate.

Let’s explore an alternative that is based on a framework that I believe would be more efficient and more likely to help the Sox win games.

The Framework

Rule one – The 7th inning rule.

If losing in/after the 7th only the hitters can challenge.

If winning in/after the 7th only the catcher can challenge (when catching).

This is a simple rule with a simple aim. Say you are losing 3-0 in the 7th, there is very little value in keeping an extra run off the board if you cannot score 3 runs to tie the game anyway. Give the batters the challenges in this scenario and let them have a little more leeway on when to use them. The inverse is true if winning 3-0. Ultimately this is about winning games.

Rule 2 – The traffic light system for hitters.

Until the 7th inning and with two challenges remaining, every player gets a traffic light colour assigned to them. (UK traffic light obviously with Red, Amber and Green options).

Green = You are free to challenge when you think you are right.

Amber = You challenge when you know you are right.

Red = You can only challenge if the ball is a foot away from the strike zone and the umpire had a medical episode to miss the call.

Two factors will decide what light someone has.

1. Are they good at challenging overall (see below, Vargas is clearly a green light).
2. Are they a hitter that does damage regularly. Mune should nearly always be a green light.

Form should also play a factor. Someone on a cold streak would be moved down to amber from green temporarily for example.

Data from baseball savant.

Sorry My Sox Summer, your boy Antonacci is getting a red light for now.

Rule 3 – Reversing the $5 on the ground strategy.

Remember when Quero had the best ABS game ever by a catcher?

Don’t worry if you don’t, it’s probably a trauma response to what we have seen since. To refresh your memory, here is an article about it.

https://www.mlb.com/news/edgar-quero-best-abs-game-white-sox-catcher-2026-season

As baseball fans, we understand leverage. Whether we are talking about count leverage, or relief pitcher leverage. What we are not seeing is any of this applied well to ABS.

We are seeing some hitters and catchers challenge more freely when count leverage matters, but with our team this doesn’t happen often as we’ve used our challenges by the 5th inning anyway. I rarely, if ever, see us using game leverage to make decisions. Rule 2 already starts addressing this.

Rule 3 is about saving the second challenge for leverage. All of the above rules can be discarded if you are in the 3^rd inning, have the bases loaded and less than two outs. You are looking for the big inning, as this gives you the best chance to win the game. Of course, the opposite applies when in the field and they have the bases loaded.

Late in games, when games are tight leverage increases. Saving a challenge for the 8th inning, with Taylor on the mound and Judge at the plate just makes sense.

Leverage indexes already exist to find the places for when to do this.

Moving forward – assess and edit

The value of a formal framework is that it gives you something clearer that you can measure. You could run this framework for 50 games and make the appropriate tweaks to it based on the new data you collect.

Edge seeking

You may also be able to find some additional edges in what is called Levelling after enacting the rules.

Antonacci has a red light. A smart team figures this out and starts nibbling at the edges a little more knowing he won’t challenge an umpire mistake. Firstly, that’s a good thing as Antonacci has a good eye, secondly you could then move Antonacci to a green or amber light to exploit the move made against him. This actually would be proper game theory.

Ultimately, I have no idea if that would happen. What I do know is the framework gives you something fixed to move from after assessment. Currently I can’t see how we will improve our success rate without some form of framework and improvement is definitely required, for both our winning chances and our sanity.

(above are the views of English_Sox_Colin only and may not be shared by the drunk uncles of WST)

-Colin