I wouldn't have a problem with it even if he did; he can yank us fans around all he wants as far as I'm concerned, as long as it means he's yanking Shanahan around in the process. I don't take it personally. The man's got a football game to win, and some parts of the game start long before the kickoff. In fact, I kinda hope he is lying as much as he can get away with.
But in fairness to the man, he may genuinely not have known. The trainers and medical staff are evaluating these guys thoroughly several times a day at this point, and it could easily be that the knee started to swell and feel sore a few hours after the last workout, or whatever. The situation really can change hour by hour. There's probably a pretty good chance even LaFleur doesn't have any real idea right now which of these guys will be on the field Saturday.