The DP/FLEX is the signature feature of NFHS softball, and it is the source of most illegal-lineup mistakes at the high school level. The trick is understanding that the DP and FLEX are one linked pair, not two separate roles.
What each role does
Under NFHS Rule 3-3-5, the DP (designated player) bats for one defensive player — the FLEX — who plays defense but does not bat. They share a single spot in the batting order. Think of it as one lineup slot with a hitter and a fielder attached.
The move that ends the FLEX’s game
The DP may also play defense, including taking over the FLEX’s position. But when the DP takes the FLEX’s defensive spot, the FLEX leaves the game. Coaches do this by accident and are surprised to find they have lost a player. If you want the DP to field without ending the FLEX, they must take a different player’s spot, which starts a different chain of substitutions.
Re-entry
Any starter, including the FLEX, may leave and re-enter once, returning to the same position. A removed substitute may not re-enter. Because the pairing interacts with re-entry, tracking each player’s status matters.
Keep it simple
Set your DP and FLEX before the game and change the pairing as little as possible. Our High School Softball builder keeps the DP and FLEX linked, tracks re-entry, and flags illegal moves before they cost you. Always confirm against the current NFHS softball rulebook.