(Now, THAT'S Trivia #11) Eight Is Too Much

Today's trivia question actually sort of ties into the sort of theme that I've had going on this week, which is a bit of a hint to the answer, by the way?

The role of oldest son David Bradford was played for most of the run of the TV series Eight Is Enough by Grant Godeve, but another actor assayed the part in the original pilot. Who was this actor and why did he give up this shot at stardom, or at least steady work?

The answer, my friends, is blowing in The Answer Blog.