Official Rules(view all)

NCAA 7-10b, 1-12-a, b Pen

If a batter hits with an altered or flattened bat as opposed to illegal bat, the bat is replaced if detected before the first pitch. If detected after the first pitch, the batter is declared out and no runners may advance.

[OBR 6.03a4: The batter is ejected and out; runners return, any other outs stand.]