Runner retreats - FED rules

[MD Longhorn]

Originally Posted by rbmartin

I know the Batter/runner may not retreat to avoid a tag (softball only).

Not completely true... and the untrue part is why you've still got the question -

Does the same apply to a runner already on base at the time of pitch?

Here's what you're missing...

BR cannot retreat TOWARD HOME to avoid a tag. If BR retreats between 1st and 2nd to avoid a tag, it's completely acceptable (and common, really). Similarly, if any other retreats between any bases other than home and 1st, it's completely acceptable as well.