According to the Major League Baseball Official Rules:
Rule 6.05: "A batter is out when ... (c) A third strike is not caught
by the catcher when first base is occupied before two are out ...."
Rule 6.09: "The batter becomes a runner when ... (b) The third strike
called by the umpire is not caught, providing (1) first base is
unoccupied, or (2) first base is occupied with two out; When a batter
becomes a base runner on a third strike not caught by the catcher and
starts for the dugout, or his position, and then realizes his
situation and attempts then to reach first base, he is not out unless
he or first base is tagged before he reaches first base. If, however,
he actually reaches the dugout or dugout steps, he may not then
attempt to go to first base and shall be out."
"Official Rules: 6.00 The Batter"
In summary, under these rules, a batter may try to advance to first
base on a third strike that is not caught by the catcher, if first
base is unoccupied or first base is occupied with two out. The batter
is out in this situation when first base is occupied before two are
I'm a life-long baseball fan, and I didn't know this before! (Though
now that I think about it, I recall seeing a game where a batter was
called out on a dropped third strike. Now I know why.)
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