How To Win MLB DFS: Stokastic Sims Find The Forgotten Stack
July 27, 2026
On a lot of MLB slates the team that wins you the tournament is the one the field forgot to roster, and no amount of staring at projections tells you which team that is. The Stokastic MLB Sims will. Baseball is the most correlated, most complex sport in daily fantasy, with nine hitters batting in order, stacks that live and die together, and a field that builds lineups in a dozen different shapes, so the contest generator is one of the most complex tools we have ever built, and learning to drive it is how you win MLB DFS tournaments. The good news is the complexity lives on the back end. Your job is a two-tool loop: build a pool of lineups that mirrors what the field will do, then simulate the slate so the tool tells you which of those lineups actually win money. This guide walks that loop end to end, and it centers on the one setting most players never touch, the setting that quietly decides which lineups you should enter.
In Summary
- Win MLB DFS In Two Tools: the contest generator builds a pool of lineups, and the MLB Sims play that pool against itself 40,000 times to rank every build by simulated ROI.
- Build To Match The Field, Not Just Yourself. Roughly 25% of the MLB field plays unstacked lineups, so leaving some unstacked builds in your pool makes the simulation more accurate, even though stacking is what you actually want to play.
- Match Percent-To-First To Your Contest before you trust the sort. A flat contest and a top-heavy flagship reward completely different lineups.
- Sort By Simulated ROI and read the diagnostic tabs, Player ROI, Stack ROI, and Exposures with leverage, to see who is carrying your lineups and which overlooked team the field is under-rostering.
- Shape The Pool Without Rebuilding. Per-team and per-player ROI boosts plus exposure caps move your builds toward the leverage you want in seconds.
Watch The Video
Prefer to follow along on screen? Here is the full walkthrough of the MLB contest generator and Sims tools.
What The MLB DFS Sims Actually Do
An optimizer builds lineups. The MLB Sims judge them. You start in the contest generator, where the base package builds up to 500 lineups and the Pro package builds up to 5,000, then those lineups carry straight into the Sims with no re-upload. Press run contest simulation and the tool plays your entire pool against itself, pitch by pitch and batter by batter, across 40,000 simulated tournaments. When it finishes, every lineup comes back ranked by simulated ROI instead of just a projected score. That full-field view is why we treat the Sims as the last step before you enter, not the first, and they run on the same Stokastic numbers behind our free MLB DFS projections, ownership and stacks in the DataHub.
Build A Contest Pool That Matches The Field
Before you can simulate anything, you need a pool of lineups that looks like the contest you are entering, and this is where MLB diverges hard from a sport like basketball. In the contest generator you set your stack exposures: how often the pool builds a 5-3, a 5-2-1, a 5x, a 4-4, a 4-3-1, a 4-2x, a 4x, a 3-3x, and so on. On FanDuel the biggest stack is four hitters rather than five, and pitchers never count toward a hitter stack. The defaults are tuned to match what the real field does, and the most important part of that is leaving some lineups unstacked.
That sounds wrong, because stacking is how you win MLB DFS. But the pool is not the lineups you want to play, it is a model of the whole field, and our research shows about 25% of that field submits unstacked lineups. Leave that 25% in and the simulation reads the slate accurately; force the pool to 100% stacked and you are simulating a tournament that will not exist. Because MLB has so much correlation, the generator can also land a player a bit under his ownership projection: in the walkthrough a hitter projected for 32% ownership was only 24% owned inside the pool, so a quick ownership boost pulled him back in line to 33% ownership, matching his projection. Scan for those gaps, boost the outliers, and rerun the pool before you simulate.
Quick tip: Do not force the pool to 100% stacked to make it look like your ideal builds. The pool is a model of the field, so the accuracy comes from letting it include the roughly 25% of entries that never stack.
Set Your Inputs: Site, Slate, And Percent-to-First
Three inputs decide everything the Sims hand back.
Your site and slate. Set DraftKings or FanDuel to match where you are playing, and pick the right slate, main, early, or night. Build a pool for one site and simulate it on the other and nothing lines up.
Your projections. By default the Sims run on Stokastic projections. To trust your own numbers instead, click upload custom projections, grab the template, and paste in three columns, player name, ownership, and projection. You can also nudge a single player on the fly, typing 22 fantasy points over a default 20.2, then roll it back with one button.
Your percent-to-first. This is the lever promised up top, and it is the one most players leave on default. It tells the Sims how top-heavy your contest is. The math is simple: divide what first place pays by the total prize pool. In the walkthrough, a DraftKings opening-day flagship carried a $500,000 prize pool and paid $100,000 to first, so first place is 20% of the pool and you select the 20% option.
Get those right and the columns mean something. Get them wrong and you are ranking the wrong lineups perfectly.
Run The Sim And Read The Columns
Run the simulation and your lineups sort by simulated ROI by default, and that default is deliberate. Simulated ROI is the all-encompassing number: it already folds in how often a lineup wins, how often it finishes top 10%, and how often it cashes. Sort by cash percentage alone and you will surface safe lineups that rarely take down first place; simulated ROI keeps the ceiling in the picture.
| Column | What it means | How to use it |
|---|---|---|
| Simulated ROI | Return of the lineup vs the field across 40,000 simulated tournaments | Primary sort; play the top of this list |
| Projected Fantasy Points | Raw projected score | A ceiling read, not a win read |
| Ownership Sum | Total projected ownership of the lineup | Lower sum = more contrarian build |
| Stack / Stack Type | Which teams you stacked, and the shape (5-3, 4-3-1) | Spot heavy vs balanced builds |
| Win % / Top 10 % / Cash % | How often the lineup wins, finishes top 10%, or cashes | Floor vs ceiling balance |
| Dupes | How many rivals submit the same lineup | Critical on small slates (below) |
The row worth staring at is any lineup with a strong simulated ROI but a low ownership sum. That is a build the field is not on, ranked highly anyway, and on a big MLB slate that is exactly the leverage a tournament pays for. Because you left that 25% of unstacked lineups in the pool, the sim can also tell you fast whether an unstacked build is quietly helping or, more often, dragging your ROI.
The One Setting Most People Skip: Match Percent-to-First To Your Contest
Here is why percent-to-first reorders your entire list. In a flat contest, where first place takes only a small slice and roughly the top of the field all win a similar amount, set it low, around 5%, and the Sims reward high-floor, high-cash builds. In a top-heavy flagship like that $500,000 opening-day contest, push it to 20% and the Sims reward the ceiling lineups and the extra leverage you need to beat thousands of other entries for the top prize. The same pool sorted for a flat double-up and sorted for a top-heavy flagship are two different lists, so set this before you favorite a single lineup. When you want to run the same idea for a low-variance bankroll, our guide to using the Sims for cash games shows how the settings shift.
The one-line version: Match percent-to-first to your contest first. Keep it low for flat contests, push it to 20% or higher for a top-heavy flagship, and let the Sims re-rank your pool for the contest you are actually entering.
A Worked Example: Finding The Team The Field Forgot
Sorting is step one. Shaping is where you win, and the Exposures tab is where it happens. (Our full guide to building winning DFS lineups in the Sims drills into these controls.) It lists every player by exposure, pool ownership, and leverage, the gap between how often the field rosters a player and how often you do. In the walkthrough the Sims kept jamming the Washington Nationals: the field was underrating them, so they graded 1st in both the 3-man and 4-man Stack ROI in the run, and they ended up as four of the top five most-rostered players in the top 150 lineups. That is the overlooked team the field forgot, surfaced by the sim rather than a hunch.
| Tab | What it ranks | The read |
|---|---|---|
| Player ROI | Every hitter and pitcher by average simulated ROI | Fade the bottom of the list |
| Stack ROI | Each 3-, 4-, and 5-man stack by profitability | Where the Nationals announced themselves |
| Exposures | Your lean per player vs the field, with leverage | Find who you are over- and under-weight |
The row that matters here is the Stack ROI tab: the Nationals topping both the 3-man and 4-man lists is the tell that pushed them into so many of the top lineups, before you ever opened the Exposures view.
You can then reshape without rebuilding. A per-team ROI boost moves a stack up or down: a -15% boost on the Nationals pulled them from about 50% of the top lineups down to roughly 24%, while a +10% boost on the Astros would push them the other way. The same works player by player, a +15% boost took Jesus Luzardo from 35% of lineups to 59%, and after any boost you unfavorite and re-favorite your top 150 to apply it. When you would rather set a hard ceiling, an exposure cap does it instantly: cap Tyler Glasnow, who was landing in 63.3% of lineups against just 27.5% pool ownership, at 40% and the tool trims him to exactly that. For a deeper tour of how far to move these knobs, see our Stokastic Sims settings guide.
Dupes: Why Small Slates Are Different
The dupes column measures how many other entrants are likely to submit an identical lineup, and on a full opening-day slate with a dozen games it barely matters, because the player pool is large enough that your builds come out fairly unique. A two- or three-game slate is the opposite. The pool shrinks, duplicate lineups spike, and a lineup duped 15 times pays out very differently from one that is not duped at all. Because the Sims project dupes, that expected overlap is already baked into the simulated ROI, so on small slates watch this column closely and prize the unique builds.
Export And Enter
When your favorited list looks right, rank the lineups by projection and ownership, export them, and upload straight to DraftKings or FanDuel. From an empty slate, a full pool of lineups and a finished simulation take only a couple of minutes: about a minute to build the contest pool and another to simulate it. If you want to see the finished product before you build, you can try the Sims free and browse a live slate, and our MLB DFS data walkthrough covers the projections feeding it.
Where The Edge Actually Comes From
Step back and the reason this loop wins is simple. Everyone in your contest is chasing the best players in good matchups, and their projections look a lot like yours. The edge is not the projections, it is construction: knowing which of your thousands of possible lineups win the specific contest you are entering, and reading which stacks and players carry that ROI so you can lean in or fade. On a slate where the field forgets a team the way it forgot the Nationals, the Sims are the only step that surfaces it against the real field. Build a pool that matches the field, set percent-to-first to your contest, and let simulated ROI pick your builds. For a running head start on the slate, our MLB DFS picks today page carries the day's top plays.
Ready to run your own MLB DFS simulations? The full MLB Sims and contest generator live in the Stokastic MLB package, where the base tier builds up to 500 lineups and the Pro tier unlocks the full 5,000-lineup simulations. Code MLBCONTEST10 takes 10% off your first payment.
Frequently Asked Questions
What is the difference between the contest generator and the MLB Sims? The contest generator builds a pool of lineups shaped to match the field, including the roughly 25% of the field that plays unstacked. The MLB Sims take that pool and play it against itself 40,000 times, then rank each lineup by simulated ROI, so you enter the builds that win money against the field rather than the ones that just score the most points on paper.
Do I have to use Stokastic projections? No. The Sims run on Stokastic projections by default, but you can click upload custom projections, fill the template with player name, ownership, and projection columns, and simulate the field on your own numbers instead.
Why does percent-to-first matter so much? It tells the Sims how top-heavy your contest is. Divide what first place pays by the total prize pool, a $100,000 top prize in a $500,000 pool is 20%, and set that. A flat contest and a top-heavy flagship reward different lineups, so this setting reorders which builds the sim recommends.
How many lineups can I build and simulate? The base MLB package builds up to 500 lineups and the Pro package builds up to 5,000, and both carry straight from the contest generator into the Sims with no re-upload before you export to DraftKings or FanDuel.
Should I ever build 100% stacked lineups? Not for the simulation pool. Leaving about 25% of the pool unstacked makes the sim match the real field and gives you accurate ROI. You still play stacked lineups; you just want the pool to model everyone, including the players who do not stack.
More on this: MLB DFS Hub: Every Live Stokastic MLB Page · MLB DFS Strategy: How To Win At Daily Fantasy Baseball · How To Use The Stokastic MLB DFS Contest Simulator · MLB DFS Primer For DraftKings And FanDuel · How To Use MLB DFS Sims To Win On DK & FanDuel