I heard it during the Rockies/Phillies game this afternoon on the radio as I was driving. The radio announcer was explaining what would be a balk move for a left-handed pitcher's move to first. He said, "if the pitcher's knee goes past the rubber, he has to go to the plate or it's a balk." I nearly drove off the road.
Then, just a few minutes ago, I heard Ron Darling, a former Major League pitcher, say the EXACT same thing in the Cubs/D-Backs game. I'm yelling at the TV (irrational behavior, I realize, since they can't hear me

.)
Did they change the rules while I wasn't looking from "free foot past the back edge of the pitcher's plate" to "free knee past the back edge of the pitcher's plate?" I don't remember any such rule change.
Now we will have more coaches quoting the rules as they heard them on radio and TV. Thanks guys.