I remember watching a game many years ago and witnessed this on a 3-0 count and was wondering why the f*** the batter was awarded first base. The commentators (probably Fergie Olver) called it a balk. That's why i thought is was technically a balk. Anyway..
From MLB Rule 8.01 (a): From this position any
natural movement associated with his delivery of the ball to the batter commits him
to the pitch without interruption or alteration.
Rule 8.01 (d): If the pitcher makes an illegal pitch with the bases unoccupied, it shall be called a
ball unless the batter reaches first base on a hit, an error, a base on balls, a hit batter
or otherwise.
Sorry,forgot the link.
https://ca.answers.yahoo.com/question/index?qid=20120417202455AAkwuD4