Tagging up on a bobble

Question
This question pertains to a ruling made in an ASA game I was a part of.  There was a runner on third base, 1 out.  Batter hit a fly ball to left field, runner on third tagged appropriately.  The runner left third at a legal time, after the ball had hit the left fielders glove.  The problem arose as the left fielder bobbled the catch, he made the catch, just after bobbling it...the runner left for home as soon as the ball hit the fielder's glove initially, not when possession occurred.  The fielding team apealed and the runner was called out for leaving early...I was always under the impression that the runner caoul leave as soon as it hits the fielder's glove...regardless of whether he bobbles the ball or not....please help, was the call made correct?

Answer
Thanks for the question!  Sorry but you got hosed.

The runner may leave at the first touch of the ball, and as I'll show you, it makes good sense.

This situation is usually referred to as the "DiMaggio Rule" referring to Joe DiMaggio.

The rule in baseball and softball used to be, the runner could not advance on a tag up until the catch was made.  So Jumpin' Joe used to get a fly ball into his glove and have it bounce in and out of his glove (up and down, like playing catch with himself in his glove) as he ran into the infield which means no one could leave because he technically never caught the ball.  Then when he got into the infield, he would finally "catch" the ball.  The rule was then changed in both games to "the first touch" so he couldn't do this anymore.  

Another example would be a high fly ball that gets juggled in the outfield, the runner may advance on a tag up once the ball is first touched.

I hope this helps answer your question, if not please reply.