Q: P1 starts the game and pitches the first three innings. In the fourth, P1 gets the first batter out. Coach replaces with P2 who gets the second batter out while P1 goes to the outfield. P1 returns and gets the third batter out and starts the fourth inning. Coach again replaces with P2 who gets the second batter out while P1 goes to the outfield. P1 returns and gets the third batter out and completes the game.
A: Legal. Rule 3-1-2 (p. 26 of the NFHS rule book). A player may be removed as pitcher and returned as pitcher only once per inning, provided the return as pitcher does not violate he rule. Replacement pitchers (P2) must pitch to the batter until such batter is put out or reaches first base, or until a third out has been made. Whenever the pitcher returns, his count is updated with the pitches he throws.