I'm a "You'll Be Perfect When You're Dead" owner and have been slowly making my way through the book for a few years. To celebrate Harmon's 50th I picked up the book again and I just got to an entry from May 28, 2008 where he talks about a flukey situation where he had just gotten cast in and subsequently replaced in a network pilot:

"Through no effort or sacrifice whatsoever, the same day I turned in my FOX script, I was called in to audition for a series regular role on an ABC pilot. I have no talent agent and no headshots, it's just that some friends of mine created a show and couldn't fill the role of the chubby loser and thought what the hell, bring in Harmon. And I went from the audition to the studio test to the network test and everyone was saying, "sure, fine, this is the guy," and all of this happened in the span of 3 days. On Tuesday, I was a writer, on Wednesday, there was this funny joke happening where people were pretending I was an actor, on Thursday, I was an actor and on Friday, I was a hair's breadth from getting a job that would make any of my actor friends fall to their knees weeping in gratitude.

And on the following Friday it was over, with a quick, apologetic phone call. And, if you ever catch Horatio Sanz on your TV playing the former lover of Alicia Silverstone, apparently, that guy would have been me, but for the opinion of one man. Some guy in a cabin farted, and it smelled like the wrong kind of beans, and my life went down one path instead of another. And that's what my actor friends go through for a living. If they're lucky. I could never do it. I'm a writer."

And here's an article from June 1, 2008 talking about Horatio Sanz being cast in a new ABC pilot with Alicia Silverstone: