Just read this article.  Some of this we knew, much of it is brand new to me.  I love the man, and I can't read enough about him.

Read the article at Cold, Hard Football Facts.

From the article:

LeBeau's playing experiences inspired the zone blitz
“If you look at the old Detroit Lions on film (when LeBeau played), you’ll see that they blitzed a lot, so he was always in man coverage,” said Troup. “He was a very good player, but when he became coach he didn’t want to leave his corners out on an island all the time in man coverage like he was.”   The zone blitz was his way of combating the problem, especially in an era that easily favored the receiver. At least back in LeBeau's playing days, defenders could rough up receivers quite a bit more and had a fighting chance in man coverage.