Lineup

A lineup is what you actually field. Constructing it well is the whole activity in DFS, and a weekly decision in season-long play.

Roster requirements

Each sport and operator specifies positions. A typical NFL DFS roster:

Slot	Count
Quarterback	1
Running back	2
Wide receiver	3
Tight end	1
Flex (RB/WR/TE)	1
Defence	1

Nine players under a $50,000 salary cap.

The flex slot is where most construction flexibility lives, and it is usually where the differentiating decision is made.

Construction by contest type

Cash games need a high floor. You are aiming to beat roughly half the field, so consistency matters more than upside. Prioritise players with guaranteed volume, avoid boom-or-bust profiles, and do not worry about being similar to other lineups.

GPPs need a high ceiling and differentiation. Beating thousands of entrants requires an unusual outcome, so you want players others are not using, see ownership percentage, and stacking correlated players to capture upside together.

The same slate should produce materially different lineups for the two formats. Using one lineup for both is the most common structural error in DFS.

Late swap

Most operators lock each player when their game starts rather than locking the whole lineup at the first kickoff. This allows late swap. Changing players in later games after news breaks or after seeing how your earlier players performed.

This is a meaningful edge and is routinely neglected by casual players.

Multi-entry

Large contests permit multiple lineups, sometimes 150 per entrant. Serious players use optimisers to generate diversified portfolios rather than entering variations of one idea.

This is the main reason a single casual entry in a large GPP faces long odds: a substantial share of the field is a small number of players with many optimised lineups each.