Chalk of the Day, August 24: Buxton to homer at +200

The chalkiest home run prop on the Monday board, checked against 5,000 play-by-play simulations of the Twins at the Athletics. The +200 price implies 33.3%. The simulations say 29.5%. Negative EV at about -12%; it becomes a play at +239 or longer.

Written by Jesse, NegativeEV. Last updated 24 August 2026.

• Sample: 5,000 pitch-by-pitch simulations of one game
• Window: 24 August 2026 slate
• Priced at: +200 at BetOnline, as quoted off the board at publication
• Measured: 2026-08-24

The bet

The check:

This is the most-bet home run prop on Monday's board, and the simulations disagree with the price on it. 10 games had odds, 10 of the chalkiest selections were graded against the sims, and the verdicts came back 8 Negative EV, 1 Roughly Fair, 1 Positive EV. Nobody here is picking anything. This is a price the public is already taking, checked.

The board ran from +181 to +222 on this prop across 6 books at the time of the check. Every one of those prices is short of +239, so where you shop changes how much this costs you, not whether it costs you.

This prop is quoted over-only, so there is no two-sided market to strip the book's rake out of. The honest comparison is the simulated number against what the quoted price implies, and some of that gap is the rake itself.

What the simulations did

Across 5,000 simulations Buxton's average is 0.34 home runs and the median is 0. The most common outcome by a distance is none at all.

The shape of 5,000 simulations:

The anytime line pays the same for all of the multi-homer games, and there are 3.8 in every 100 of them.

At 5,000 simulations that 29.5% carries a standard error of 0.64 points, so 95 runs in 100 would land between 28.2% and 30.8%. The gap to the price is about 4 points, roughly 6 times that error bar. Said narrowly, and it should be said narrowly: that means only that re-running the simulator would not move the number far enough to reach the price. It is not a claim that we are right and the book is wrong. A number that is systematically off is off to as many standard errors as you like.

How many cracks he gets

Buxton bats on the away side, which is the cleanest thing working for him: he is guaranteed all nine innings, and there is no scenario where his side is up after eight and he loses a turn. Across the runs he comes up 4.55 times on average, at-bats plus walks, and the home run number moves with that count.

Trips to the plate, and what each one is worth:

Pooled across every simulation he goes deep on 7.4% of his trips, so whether he bats one more time or one fewer is worth more here than any read on his swing. That extra trip is not his to take either. It depends on the eight hitters around him keeping the order moving, and in the simulations they do not always do it.

What works for him

Four arms clear their own noise on this side, and together they are the story.

• His own career profile, who he is as a hitter, props the number up by about 6.9 points. Neutralize it and 29.5% becomes 22.6%. HR rate .080, 9 of 313 hitters, top 10%. BABIP .286, 199 of 313 hitters, middle of the pack. K rate .278, 264 of 313 hitters, bottom quarter. Exit velo 91.7, 30 of 313 hitters, top 10%. Launch angle 19.8, 298 of 313 hitters.
• The weather props the number up by about 4.6 points. Neutralize it and 29.5% becomes 24.9%. That arm neutralizes temperature, wind and conditions at once, so the cause is not separable. It is 86 degrees with a 10 mph wind blowing out to centre.
• His own season form props the number up by about 4.2 points. Neutralize it and 29.5% becomes 25.3%. HR rate .081 against .080 for his career, 8 of 313 hitters, top 10%. BABIP .279 against .286 for his career, 213 of 313 hitters, middle of the pack. K rate .247 against .278 for his career, 218 of 313 hitters, middle of the pack. Exit velo 90.4 against 91.7 for his career, 74 of 313 hitters, top quarter. Launch angle 20.6 against 19.8 for his career, 298 of 313 hitters.
• Playing on the road props the number up by about 1.3 points. Neutralize it and 29.5% becomes 28.2%. He is guaranteed all nine innings, whatever the score after eight.

The pitcher

A left-hander, 1,872 pitches into the season and ranked against the 571 pitchers with enough of them to compare. He releases from a high three-quarters slot, 6.0 feet up (82th percentile) and 2.04 feet across (66th), with 6.37 feet of extension (44th percentile).

The ballpark

Sutter Health Park ranks 1st of 30 for home runs, with a park factor of 1.47 where 1.00 is neutral. It is one of the friendlier parks to hit one in. In the 2026 data home runs land on 6.2 of every 100 balls in play in the Athletics' home games against 4.2 in their road games, 3,133 batted balls at home, 2,615 away, the same club on both sides of the split, so what is left is the park. Open roof, grass, 330 feet to left, 403 to centre, 325 to right, 24 feet of elevation. Tonight it is 86 degrees with a 10 mph wind blowing out to centre.

Byron Buxton, recent against season:

• usual lineup spot: 1st (over 88 games)
• plate appearances this season: 384
• plate appearances in the recent window: 20

Those are the inputs the simulator was served, not a separate stat source.

The rest of his night

The home run does not arrive alone. Split across the 5,000 simulations on whether it lands:

:

The game itself averages 8.87 total runs. His side scores 6.07 when the homer lands against 4.12 when it does not, so this is not an isolated event - it travels with the whole offence.

What this does and does not say

It says that at +200 the price is asking for more than the simulations produce. It does not say he will not homer. He goes deep in 30 of every 100 simulated games. Every play is relative to its price, and the two numbers meet at +239.

Method

The game is simulated pitch by pitch 5,000 times from the projected lineups, and the prop is graded on how often it lands. 38 factors were neutralized one at a time, each arm a separate 4,000-simulation re-run, so one-at-a-time swings do not sum to the projection. Those 38 cover everything that could bear on this hitter rather than every factor in the game: the other hitters' own career, season and recent tiers were skipped on purpose, because they are most of the cost and none of the answer for a prop about one man. 13 of the 38 came back with a direction we can stand behind. The price is +200 as quoted at BetOnline at publication, and the check is against that quoted price, rake included.

Inside the noise floor

25 of the 38 arms sit inside their own noise, including Jeffrey Springs's career profile, the pitcher he faces (+0.9), his own recent form (-2.0), Jeffrey Springs's season form (-1.0), the rest of the order, the other eight, without him (-0.9), the ballpark (-0.9), what Jeffrey Springs has been throwing lately, his pitch mix (-0.9), batting 2nd today instead of his usual spot (-0.6), how long Jeffrey Springs stays in (-0.3). Those numbers are real measurements and they are printed rather than dropped, but at this simulation count the arm cannot tell a small real effect from no effect. So none of them does nothing, and none of them can be named the thing driving this.

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