01 · STACKS
5-3, 4-4, 5-2-1 AND MORE
Choose the stack types your portfolio uses and how often. DraftKings' five-hitter max is enforced automatically.
Baseball runs come in bunches. DFS Only plays every slate out 100,000 times with hitters in the same lineup rising and falling together, then builds each lineup for its own simulated night — while you keep control of stacks, pitchers, and exposures.
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Tournament-winning MLB lineups are built on stacks because runs are not independent events. A single, a walk, and a three-run homer put points on four hitters from the same inning. A one-off lineup — one hitter from eight teams — can be well researched and still have no path to first place. The MLB stacking guide walks through the math.
DFS Only builds lineups the way slates actually break. Each lineup draws its own simulated night from the 100,000. Teams that beat their own normal in that world are the stack candidates, and every player is valued at what he scored there — so your portfolio spreads across the offenses that can erupt, not just the two highest implied totals everyone else is on.
Turn the diversity slider down and you are building toward pure projections for cash games. Turn it up and every lineup becomes a different simulated slate. Either way you set the stack types, team allocation, pitcher caps, locks, and fades.
Choose the stack types your portfolio uses and how often. DraftKings' five-hitter max is enforced automatically.
Set stack percentages by team, or hit SIM to fill them from how often each offense finished as a top run-scorer across the simulations.
Sim P writes pitcher max exposures from the sims as a starting point. Adjust anything by hand — and never stack against your own pitcher.
Machine-learning projections weighted for matchup, park factor, temperature, wind, implied runs, and spot in the batting order.
A scratch an hour before first pitch? Swap him out and re-optimize the open spots around the players already locked.
Score your saved lineups against a simulated field for a contest's size and payout — cash rate, ROI, EV, and top-1% odds per lineup.
Sim win rate minus projected ownership. Find the hitters who win the sims more than the field expects.
Classic and Showdown Captain Mode, with a DraftKings-ready CSV for bulk upload.
Main, early, late, turbo, or Showdown.
Weather and game environment, matchups against tonight's pitchers, leverage plays, and value plays.
Stack types, team allocation, pitcher caps, locks, fades, and exposure limits.
Each lineup is built for its own simulated night, with your rules enforced across the portfolio.
Score your lineups against a simulated field, late swap if needed, and upload the CSV to DraftKings.
Everything is included either way — projections, simulations, leverage data, and the full optimizer. No upsells.
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Get Pro →The best one is the one that matches how you play. If you want every lineup built inside correlated simulations — with full control over stacks, team allocation, pitchers, and exposure — DFS Only is built for that. The MLB optimizer comparison covers the trade-offs honestly.
DFS Only doesn't have a free tier, but the MLB day pass is $5 and unlocks the full MLB tool for 24 hours with no subscription — projections, 100,000 sims, leverage, the optimizer, and CSV export.
5-3 is the most common winning structure, with 4-4 and 5-2-1 close behind. The right one depends on the slate — 5-3 when one offense stands out, 4-4 when two games look equally explosive. Many players mix structures across a multi-entry portfolio.
Five. Pitchers don't count toward the limit, which is why the five-man stack is the largest primary stack on DraftKings Classic.
Yes. After lock you can swap players in games that haven't started and re-optimize the open spots around everyone already locked in.
It scores your saved lineups against a simulated field of a contest's size and payout structure, returning cash rate, ROI, EV, and top-1% odds for each lineup before you enter.
Not yet. It is built for DraftKings salaries, roster rules, and scoring. FanDuel support is on the roadmap.
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