MLB Home Run Odds Today: Kalshi Prices Vs. Stokastic Sims

Edition 1 · Wednesday, August 12, 2026 · Panel record: 0-0 (first edition, nothing graded yet)

This page is two things at once: an information board covering every Kalshi MLB home run market with a live quote today, and a set of graded calls on the three spots where the Stokastic Sims and the market disagree most. We rebuild it every day at this same URL, and every call gets graded against Kalshi settlement the next morning. The Sims' hrPercent is the only probability we publish; we never mint a number the model didn't produce.

Today's board rewards selectivity. Kalshi lists 66 hitter markets for today's 14 games, but only 35 of them had a live two-sided quote when we pulled prices around 12:10 PM ET. Where the market is actually trading, three gaps stand out, and our six-seat panel refused the biggest of the three over the hitter's own contact quality.

Junior Caminero — one of the featured players on today's slate.

The Quick Answer

Kalshi's MLB home run markets today run from Junior Caminero at 27¢ down to Steven Kwan at 3¢, and the Stokastic Sims disagree with three quotes by 4.5 points or more: Gunnar Henderson (+5.9), Pete Alonso (+5.0), and Yordan Alvarez (-4.5). Our six-seat AI panel backed the Sims on Alonso and Alvarez but sided with the market on Henderson. The full 35-market board, the three gap breakdowns, and the seat-by-seat votes are below.

Today's Kalshi Home Run Odds Board

Prices are Kalshi's yes bid/ask in cents as of 12:10 PM ET on August 12, with the American-odds equivalent at the ask. Sims HR% is the Stokastic Sims' own home run probability for today's games. Gap is Sims minus the bid/ask midpoint: positive means the Sims see more home run than the price, negative means the market is paying up beyond what the Sims project.

The row that jumps off this table is the one at the top. Gunnar Henderson carries the single biggest gap on the board at +5.9, and he's doing it with a 7.5% barrel rate this season; that barrel rate is the crux of the panel's Henderson vote below. One honesty note on coverage: the other 31 listed markets showed no live bid at pull time. Kalshi's home run listings run thin like this most days, so a hitter missing from this table usually means no market, not no power.

The two priciest names on the board tell the other half of the story. Caminero (27¢/28¢) and Ohtani (25¢/26¢) are the board's most expensive hitters, and the Sims essentially shrug at both quotes, landing within half a point of the market. When the model and the market agree that tightly on the chalk, the interesting money is in the disagreements, which is exactly where we're headed. For the same treatment of moneyline markets, our daily Kalshi MLB picks board runs the Sims against game winners every morning.

The Three Biggest Gaps, Voted On By A Six-Seat Panel

We put each gap to a panel of six independent AI seats. Every seat got the same verified inputs (the Statcast contact profiles, the opposing starter, the park, the Sims number, the market price) and had to side with either the Sims or the market. Six seats, one line each, majority rules. No seat saw another seat's answer.

Gunnar Henderson: Market 16¢/17¢ (+488), Sims 22.4% — Panel Sides With The MARKET, 5-1

Henderson is in Baltimore's posted lineup against Twins right-hander Zebby Matthews at Target Field, a neutral home run park (101 factor). The matchup case is real: Matthews has allowed a 12.3% barrel rate and a .446 xSLG, a distinctly homer-prone contact profile. The problem, and here's that number again, is Henderson's own bat: a 7.5% barrel rate, .396 xSLG, and 46% hard-hit rate in 2026. The Sims still make him 22.4% to homer today; the market says 16-17 cents.

• Seat 1 (Market): Henderson's modest 7.5% barrel rate and .396 xSLG undercut such an elevated projection; the lower price better fits his contact despite the friendly matchup.
• Seat 2 (Market): His own 7.5% barrel rate and .396 xSLG are pedestrian power marks that don't justify a 22% projection in a neutral park.
• Seat 3 (Market): 7.5% barrel rate and .396 xSLG are middling power marks that don't support sims pricing him near 22%, even against a generous arm.
• Seat 4 (Sims): Neutral Target Field plus a starter allowing .446 xSLG and 12.3% barrels supports the higher read over the 16-17 cent line.
• Seat 5 (Market): Low barrel rate and xSLG relative to pitcher allowed rates justify market's more conservative estimate over simulation.
• Seat 6 (Market): Low barrel rate 7.5% suggests market's 16-17 cents better reflects actual home-run probability.

Five of six seats read Henderson's contact quality as the reason the Sims number runs hot, so the biggest gap on the board goes in the book as a pass, not a call.

Pete Alonso: Market 19¢/20¢ (+400), Sims 24.5% — Panel Sides With The SIMS, 5-1

Alonso, in the lineup for Baltimore after his deadline trade, draws the exact same Matthews matchup, and his bat is a different animal: a 14.1% barrel rate, .536 xSLG, and 56% hard-hit rate. Elite contact against a starter who bleeds barrels is the cleanest matchup fact among today's three gaps, and the Sims price it at 24.5% against a 19-20 cent market.

• Seat 1 (Sims): Alonso's 14.1% barrel rate, .536 xSLG and heavy hard-hit contact against a homer-prone starter justify the projection above the market price.
• Seat 2 (Sims): Elite 14.1% barrel rate and 56% hard-hit against a barrel-prone right-hander is exactly the physical profile the lower market price underrates.
• Seat 3 (Sims): 14.1% barrels, .536 xSLG and 56% hard-hit against a starter allowing 12.3% barrels and .446 xSLG back the higher sims number.
• Seat 4 (Sims): Elite 14.1% barrel rate and .536 xSLG against a homer-prone arm in a neutral park backs the higher number over 19-20 cents.
• Seat 5 (Sims): Alonso's elite barrel rate, hard-hit percentage, and xSLG substantially exceed pitcher's profile, supporting higher simulation estimate.
• Seat 6 (Market): Even elite power (14.1% barrel, 0.536 xSLG) doesn't justify sims' 24.5% in single at-bat.

Graded call #1: the panel takes the Sims side, which maps to YES at 20¢. If Alonso homers in this afternoon's game, this grades a win; if not, a loss.

Yordan Alvarez: Market 21¢/22¢ (+355), Sims 17.0% — Panel Sides With The SIMS, 5-1

The third gap runs the other way: the market is paying more than the Sims think the spot is worth. Alvarez owns the best raw contact profile of the three featured hitters (17.9% barrel rate, .687 xSLG, 54% hard-hit), and 21-22 cents prices exactly that reputation. But he's hitting at Oracle Park, a strong home run suppressor (90 park factor), against Giants right-hander Adrian Houser, who has allowed just a 9.0% barrel rate. Houston's lineup also wasn't posted for the 3:45 PM ET start when we pulled prices, which the seats weighed too.

• Seat 1 (Sims): Oracle Park's strong home-run suppression supports the lower number; the market overpays for elite reputation while underweighting the park and unconfirmed lineup.
• Seat 2 (Sims): A strong home-run suppressing park and an unposted lineup argue for the lower projection, so the elevated price looks overstated here.
• Seat 3 (Market): 17.9% barrels and .687 xSLG are elite enough to outweigh the Oracle Park suppression that's dragging sims below market.
• Seat 4 (Sims): Oracle Park's strong HR suppression plus an unconfirmed lineup argue for the lower read against the 21-22 cent price.
• Seat 5 (Sims): Oracle Park's strong suppression factor adequately tempers elite fundamental profile in simulation versus market underweighting of venue.
• Seat 6 (Sims): Oracle Park's suppression and Houser's 9% barrels allowed override Alvarez's elite 17.9% barrel rate.

Graded call #2: siding with the Sims here means the market is too high, which maps to NO at 79¢ (buying the no side of a 21¢/22¢ yes market). If Alvarez goes homerless, it grades a win.

A Worked Example: What The Alonso Call Actually Pays

Walk through the math on the Alonso call so the cents-first format never feels abstract. A Kalshi home run contract settles at $1 if the hitter homers and $0 if he doesn't. Buying Alonso YES at the 20¢ ask means risking 20¢ to win 80¢, which is +400 in American odds and a 20% implied probability. Our Sims put the same event at 24.5%. If the Sims number is right, that 20¢ contract is worth 24.5¢, a 4.5-cent difference on a 20-cent stake. The Alvarez call is the mirror image: NO at 79¢ (the price to buy the no side against a 21¢ yes bid) risks 79¢ to win 21¢ (-376 American, 79% implied that he stays in the yard), while the Sims' 17.0% home run probability implies the no side is worth 83¢. Same logic, opposite direction. If cents-to-odds conversion is new to you, our Kalshi vs. DFS pick'em apps comparison walks the pricing mechanics from scratch.

How These Calls Grade

Settlement is the whole scoreboard here: each Kalshi 1+ home run contract settles YES at $1 the morning after the game if the hitter homered, and NO at $1 if he didn't, per the market's official result. Two calls go in the book today: Alonso YES at 20¢ and Alvarez NO at 79¢. Henderson is a pass, because a panel that sides with the market is saying the price is right, and there's nothing to grade in agreeing with the price. Every call grades against Kalshi settlement only, tomorrow morning, and the running record posts at the top of the next edition. Edition 1 starts 0-0, so the record line above is exactly as empty as it should be. No projections get graded, no partial credit, no revisions after first pitch.

If you want the longer-horizon version of the same discipline, our AL Central model verdict and the Kalshi MLB playoff odds board run panel calls on season-length markets with the same no-revisions rule.

What An HR Lean Means For Your DFS Lineups

Here's the part the home run market can't give you: the same hrPercent that flags a mispriced Kalshi quote is a leverage signal in MLB DFS projections, ownership and stacks in the DataHub. Alonso is the clean example today. Today's Sims run gives him the third-highest home run probability on the priced board (24.5%, behind only Caminero and Ohtani) at a $3,400 FanDuel salary and just 6.9% projected ownership. A hitter the field is rostering at 7% who clears the fence a quarter of the time in the Sims is exactly what leverage looks like. Contrast Ohtani: the board's second-highest hrPercent at 26.0%, but at $4,100 and 24.6% ownership, the field already knows.

The panel's Henderson pass cuts the same way in DFS. His $2,900 salary and 8.7% ownership look tempting, but five seats just told you the 22.4% hrPercent is the number to distrust today, and the Sims' edge cases only pay when you trust the input. That crossover reading, market gap to lineup decision, is the whole reason a DFS player should care about prediction market prices at all; we wrote up the general framework in Prediction Markets for DFS Players and priced Kalshi against the pick'em apps in Kalshi vs. DFS Pick'em Apps. You can run today's full slate yourself with the Sims free before lock.

Ready for the full toolkit? Stokastic Pro puts the Sims' hrPercent, ownership, and stack projections behind every lineup you build, and code KALSHIHR10 takes 10% off your first payment.

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