WiiSports

Is there a way to always execute the splitter properly, or does the game randomly determine it?

When I try to throw a splitter, sometimes my guy ends up throwing a fastball instead as a big red exclamation point (!) appears above them. It’s a problem because usually it becomes a meatball that the opponent ALWAYS smacks for a hit. Is there a way to avoid this? Or is it completely random when it happens?