A keeper league lets each manager carry a small, fixed number of players — commonly two to five — from one season into the next, then redraft everyone else in a full draft. It sits between redraft, where every roster resets to zero each year, and dynasty, where you keep your entire team.

The number of keepers and the cost to hold them is the design that gives a keeper league its character. Many leagues charge a draft pick to retain a player — keep last year’s breakout and you forfeit the round they were drafted in — which forces a real decision about whether a star is worth the pick you’d surrender.

The distinction from dynasty matters for how a commissioner runs the offseason: keeper leagues still hold a full startup-style draft every year, while dynasty leagues only draft rookies and free agents after their initial startup.