DraftKings has a new "game theory" promo in which you have to bet a player to hit a home run, and if they hit a grand slam, you split a $250,000 prize pool with all other users who selected that player. If no one hits a grand slam on that day (which happened 52% of days in 2025), the pot rolls over to the next day.
DK runs something similar (although far less random) with their NBA King of the Court promo. And Fanatics got in the game this MLB season with its longest home run jackpot.
But unlike King of the Court, where you can bet the NBA player likely to lead the slate in points, rebounds and assists with some certainty, trying to pick who will hit a grand slam is very, very random. You can parlay up to three players for this promo, which does increase your chances from sub 0.5% in a given day to maybe north of 1%, depending on who you pick.
I built a quick data visualization tool you can dive into (though the data is super noisy), with a few summary tips below.
1. There's less than 1 grand slam per day across MLB
On a 15-game slate, we can expect about 0.7 grand slams per day. About 51% of days with MLB games since the start of 2024 have ended without a grand slam.
On a full slate, you have ~270 players to choose from (assuming DraftKings lists every player). So your chances of hitting this promo are quite small.
Even Aaron Judge, who our projections give a 38% chance to homer on Friday, is at less than 1% to hit a grand slam.
2. No team had more than 10 grand slams in 2025; no player more than 3
Because this is a game theory promo, you want to avoid the most popular selections so that if you do win, you take home a bigger share of the $250,000 prize pool. Fortunately, the better home run hitters aren't necessarily hitting grand slams, so it's not hard to avoid them.
There were 21 players who hit 2+ grand slams in 2025, and seven of them hit 20 or fewer home runs the whole season. Kyle Schwarber hit two; Shohei Ohtani 0; Aaron Judge just one.
3. There's a ton of noise in team data
I had some narrative-driven takes before I looked at the data.
- High OBP teams that walk and hit for contact will hit more grand slams than three-outcome teams, because the bases will be loaded more often (this is wrong)
- Total home runs will highly correlate with grand slams (some truth to this)
So as we've learned, grand slams are quite random.
Over the past three seasons, the Diamondbacks have hit 22 grand slams — eight ahead of the next team. That makes some sense since they ranked first, then seventh in on-base percentage in those seasons, and fourth in total home runs.
But then take the Dodgers — they have just 11 grand slams despite having a nearly identical OBP over the last two seasons and 62 more total home runs. Or the Pirates, who also have 11 grand slams in that time frame, but the fewest home runs in the league (209 fewer than the Dodgers).
4. As always, ignore the most-selected players
Because you're sharing the prize pool with everyone else who took the players that you did, you'll want to avoid players with the best chance to hit homers, and the players highly recommended on Twitter for the day.
Just spray and pray.
