AI Lineup Optimizer

In GameChanger, open your team's season and export the combined stats as a CSV — the one that carries batting and pitching together. The file is read in your browser and is never uploaded; what gets sent is the roster it produces. Where that goes is worth knowing, because it is children's data — see what happens to my players' data? below.

Start by marking anyone who is not at this game out — an export is your season roster, a lineup is one afternoon, and the order is built only from the players you leave in. Then the part a box score cannot see: it does not know who is genuinely fast, who hits the ball hard without the average to show for it, or who bats left. Signed in, you rate each player for speed and power and set their handedness — and in fastpitch you can mark your slap hitters, which is the one thing a stat line reads backwards. Those ratings are weighed alongside the numbers rather than overriding them. A signed-out run is built from the export alone, which is a perfectly good starting point — the ratings are what turn it into your roster rather than a stat line.

Nine for a standard order, or all the way out to your full roster for continuous batting orders — which most youth leagues use, and which changes the job completely: with fourteen names in the order, every slot comes round, so the question is sequencing rather than who sits. Bring nine or fewer and there is nothing to set, because everybody bats.

Every slot comes back with a one-line explanation of why that player is there, plus a strategy summary for the order as a whole. Override anything you disagree with — drag a player by their slot number, or nudge them with the arrows — because you have watched these kids play and the CSV has not. The card marks whatever you moved, since the note under each player was written for the slot the optimiser gave them. Then print it for the dugout, or share it as text with an assistant.

Why on-base percentage beats batting average for the leadoff spot

The leadoff hitter's job is to be on base when the middle of the order comes up, and batting average only counts one way of getting there. Two players hitting .300 are not equivalent if one walks twice as often — over a season that is dozens of extra baserunners from the same batting average. This matters more in youth baseball than anywhere else, because walks are a far larger share of times on base at every level below high school. The fastest kid on the team is the traditional leadoff choice; the kid who reaches base most often is usually the better one, and if they happen to be the same player the decision makes itself.

Should your best hitter bat third or fourth?

Neither, if you are optimising strictly. The third spot comes to the plate with two outs and nobody on more often than any other slot in the top half of the order — it is the least valuable of the premium spots. Run-expectancy work on lineup construction has pointed at the second and fourth slots for your best hitter for years, and second is the one most coaches will not use because it looks wrong. The gap is small — a handful of runs across a whole season — which is the honest caveat: the order matters, but it matters less than who is in it.

The bottom of the order is a second leadoff

In a continuous batting order the last few slots turn over to the top of the lineup constantly, so the worst place to put your three weakest hitters is together at the end where they strand the innings that would otherwise start your best hitters. Spacing them, and putting an on-base threat in the final slot, is the single cheapest improvement available to a youth lineup — and it is the adjustment the optimiser makes most often on rosters uploaded here.

What about handedness and matchups?

Alternating left and right through the order makes an opposing manager work harder for a favourable relief matchup, and back-to-back left-handed bats invite a lefty out of the bullpen. Below high school this is worth very little — most youth teams have one or two lefties and no bullpen to speak of — so it is used as a tiebreaker between players who are already close, never as a reason to move a better hitter down.

What happens to my players' data?

The CSV itself never leaves your computer — it is read in the browser to build the roster on screen. The roster and its batting numbers are then sent to us, and the batting order is worked out on our own server from those numbers. That part involves no AI at all: it is arithmetic, and the same roster always produces the same order.

What the AI writes is the one-line explanation under each slot and the strategy summary, and to do that it is sent, for each player in the order, their name and the facts quoted in their line — on-base percentage, slugging, walk rate, steals or quality at-bats, whichever the slot cites, plus anything you set yourself, like handedness or a slap-hitter mark. Nothing else goes with it: not jersey numbers, not the pitching or fielding columns (which never leave your browser at all), and nothing about players you left out of the order. Our AI provider is named in the privacy policy, along with everyone else who processes anything here.

Does this work for softball?

Yes, and there is a fastpitch mode at the top of the page. It changes one thing, and the restraint is deliberate: on-base percentage, slugging and how many times each slot comes to the plate mean the same in both sports, so re-weighting the order by sport would be inventing numbers. A fastpitch roster with no slappers on it produces the same order the same roster would in baseball.

What does marking a slap hitter actually do?

It stops the maths misreading them. Slapping trades power for contact and speed on purpose, so a slapper's slugging percentage is low by design — and a batting order built on slugging reads that as a weak bat and buries them. Marking a slapper rates them on getting on base and on speed instead, which is what they are actually for.

It is not a promotion. There is no rule here that slappers bat leadoff — that is a convention, not a finding. A slapper who genuinely reaches base rises to the top on their own numbers, and one who does not stays where those numbers put her.

What about the DP/FLEX?

That is a roster decision you make before you get here, and this tool takes no position on it. Give it the batters who are actually in the order — ten, eleven or twelve names if that is what you are running — and set the depth to match. Availability, re-entry and who may bat for whom are your league's rules, and they vary by division and organisation.

What if I don't use GameChanger?

The importer reads GameChanger's combined stats export specifically. If you keep your book somewhere else, the practical route is to assemble a CSV with the same columns. Support for other exports is not there yet.

How many lineups can I generate?

One without an account, three a month with a free account, and unlimited on Coach or Club. Every per-player control — speed, power, handedness and the slap-hitter mark — comes with any account, free included: signing up is never a downgrade. See the plans →