Ball thrown to 1st base after BB/Walk ????

[nickrego]

Could you be more specific about the Walk.

Was it a Walk on 4 pitched Balls, or an Issued Walk ?

In some leagues, NFHS included, when you issue a Walk (elect to not pitch to the batter), the ball becomes dead. Hence, throwing to 1st is a no call, and can be considered a delay of game, if the ball isn't back to the pitcher when the next batter is ready.

With respect to the NFHS Mercy Rule:

4-2-2:...By state association adoption, the game shall end when the visiting team is behind 10 or more runs after 4 1/2 innings, or after the fifth inning, if either team is 10 runs behind and both teams have had an equal number of times at bat.