Fumbled Snaps

The rules on snap fumble chances are laid out on p77, sections (k) and (l)

The modifiers for shotgun snaps are on p56.

On every offensive play / FG attempt / punt there is a chance that the center will fail to snap the ball cleanly to the quarterback / holder / punter, resulting in the ball spilling onto the floor. Fumbled snaps are relatively rare, but as a source of turnovers cannot be ignored.

Chance of snap fumbles on Offense
Snap fumble chances are dependent on C(T), with small additions when the weather is "Rainy". As shown in the graph to the right (click to enlarge), fumble chances on regular snaps are very low (<0.5%) when C(T) = 0.5 (e.g. a level 10 45/50/5 OC).

Nose Tackles double the chance of a fumbled snap when they exert Big Pressure. They increase the chance of a fumbled snap by 0.125% for each level they are higher than the center.

Result of fumbling the snap
unfinished
 * Yardage loss
 * Turnover chance

Fumbled Long Snaps
unfinished