pitcher-fed
 

Line ups are handed in and confirmed at pregame conference. Then one coach wants to change pitchers on the line up card. Legal?
Does pitcher have to face one batter first before she is replaced?

Only if she gets courtesy run for does this become an issue.

No. There is no rule that says she must. It is common strategy to designate a player as DP on the starting lineup, then once the lineup is accepted as official, change that person to P, and designate the listed P as OP. This gives the team the option to pull that pitcher and have her still bat as the DP, also allows the FLEX as an option offensively for that player.

Once the change is reported, THAT player becomes the P "listed on the lineup" in the top of the first, and IS eligible for a courtesy runner. The rule does not say it must be the INITIAL listing and isn't subject to a reported change. However, whatever player is listed at P AND gets a courtesy runner in the top of the first must pitch to one batter, OR ELSE the penalty is that courtesy runner retroactively reverts to a substitution (and generally re-entry).

What is OP?

Offensive Player, a term only defined at the collegiate level I believe.

The player in the batting order who is not playing defense because the DP has entered to play defense.