The only example that i can think of is Roger Clemens in game 6 of the 1986 World Series. Johnny Mac swears that Clemens asked out of the game because of a blister. Roger, of course, denies the accusation. After all that has transpired recently shedding new light on Clemens' lack of veracity, Johnny mac's version of the story has to be given much more weight. I don't think one player has come right out and called Johnny Mac a liar although several have said they believed Clemens. I wonder if any of them were covering for their friend, Rocket, and I wonder if any would have a different opinion today.