This is the same as a whistle in the NFL... if a ref thinks a quarterback is "in the grass" and blows the whistle... just because the quarterback throws the ball for a first down does not mean the play counts even if he was not in the grass and the Ref says, "Yeah... I think he was not in the grass... 1st down". Once the Ref blew the whistle play is over because the Defense stops covering/tackling. Once the Ump pumped his fist, you can see Darren Erstad (the Angels 1st baseman) do the same thing and leave the field. There was no one on 1st base to throw the ball too once Erstad left. Even if the ball hit the ground, once the Ump did the fist pump, the player is out and play must end... even if the call was wrong (which it was not). The players do not need to complete every play.... games would go 5 hours if you catch a shoe string ball and the Ump calls the player out... do you still need to quickly throw the ball to first just in case?