Okay...here goes....
ASA uses the DP/FLEX rule. So does high school. I'm just going to assume that everyone knows how the DP/FLEX rule works.
NSA allows the use of an "Extra Player" (EP). A team can use either one or two EP's (they must be made known prior to the game and noted on the line-up card). These two EP's can play defense at anytime, rotating in and out of the field without being charged as a substitution.
NSA also allows the use of a "Designated Hitter" (DH). The DH bats only, the player for whom she is batting plays defense only. The player in the DH slot
may play defense, but once she does the role of the DH is eliminated for the remainder of the game.
A legal NSA line-up may have up to twelve players- nine positional players, two EP's and one DH.
USSSA uses the DH and allows one "Additional Player" (AP). The AP is essentially an extra batter, treated the same as the EP in NSA. The DH also works the same as in NSA. A legal USSSA line-up may contain up to 11 players- nine positional players, one AP and one DH.
Courtesy runners get a little tricky with all of the rules that apply to them. Basically, here's how it's handled:
ASA: May run for the pitcher or catcher, regardless of the number of outs. The CR must be a player who is not currently in the game and has not yet participated in the game.
High School: Same as ASA.
NSA: Same as ASA- EXCEPT- The CR may be a player not in the game/has not participated in the game OR the player who made the last recorded out. Of note: The "last recorded out" may not always automatically be the last batter in the line-up. Often it will be, but with multiple runners on base this will not always be the case.
USSSA: Same as ASA/high school.
I did have a chance to work games this weekend for a different sanction than I normally do. The first thing I did was get ahold of their rule book and scan through it for some of the rules that are often different. The number of players allowed in the line-up and the Courtesy Runner rules where definitely two that I checked!
Interestingly, the coaches this weekend seemed to be confused by the line-up rules, too. Hardly a game went by where I didn't have to correct a line-up before the game. There were coaches trying to "bat the entire roster", wanting to use a DP/FLEX in a sanction where one was not allowed, there was some confusion about the DH rule and one coach listed his tenth batter as his as an "SP"-
Special Player- a designation that doesn't exist in
any rule set!