by Ninersphan » Mon Mar 05, 2012 9:10 am
Here's the rules from the rule book:
[i:4f1334f165]29.1 WHEN PITCHING TO BATTERS
When rolling the three 6-sided dice to get a result from the players' cards, or when using the Bunt or Hit and Run charts, roll a 20-sided die at the same time.
A. If the 20-sided die roll is 3-20, continue with the normal reading of the three dice (if you will need the 20-sided die again to resolve this play, you must re-roll it.).
B. If the 20-sided die roll is 1, a wild pitch may occur. Refer to the pitcher's wild-pitch rating and roll the 20-sided die again. If the number rolled is less than or equal to the wild-pitch rating, a wild pitch occurs and all baserunners advance one base.
C. If the 20-sided roll is 2, a balk or passed ball may occur. Roll the white 6-sided die first. If it comes up 1, 2, or 3, a balk may occur. If it comes up 4, 5, or 6, a passed ball may occur. In either case, roll the 20-sided die again and refer to the appropriate rating (the pitcher's balk rating or the catcher's passed ball rating). If the number rolled is less than or equal to the rating, then a balk or passed ball occurs and all baserunners advance one base.
D. If your initial roll of the 20-sided die yields a 1 or 2, but no wild pitch, balk or passed ball occurs, you must re-roll the three 6-sided dice (without the 20-sided die) to continue the play. If a wild pitch, balk or passed ball did occur, you must re-roll all four dice to continue (if the bases are now empty, only the three 6-sided dice are needed). In this fashion, more than one of these events can occur while a single batter is at the plate.[/i:4f1334f165]
It's more math than I care to do to get a percentage, but it's not huge. Of course the proability of your guy having a passball if the small chance does come up is very probable.