A Great Rogers Hornsby Anecdote

I was re-watching some of Ken Burns' series Baseball last night, and I enjoyed this anecdote about the great hitter, Rogers Hornsby:

Rogers Hornsby - Perhaps the game's best right-handed hitter

Rogers Hornsby, who averaged.400 over five years, and was unquestionably one of the greatest hitters of all-time was facing a rookie pitcher. The pitcher was understanably nervous facing Hornsby at what was the height of his career, and he threw the first three pitches just barely outside the strike zone. However, the rookie pitcher thought that he thought these pitches were strikes and shouted to the umpire as much. The umpire then replied: "Young man, when you throw a strike, Mr. Hornsby will let you know."