NFL gave Vilma a sworn affidavit from Gregg Williams stating Vilma offered $10k to knock out Favre

Current Redskins linebacker Lorenzo Alexander, who played under Williams in Washington, said a player could get rewarded for knocking a player out of a game with a clean hit, but only after the fact - not as a pre-planned "bounty." Sometimes players wrote each other checks for such plays.
"It wasn't always Coach Williams" who paid up, Alexander said.

NFL bounties amount to incentive system run amok - CBS News

So Williams had nothing to do with adding in the part about knocking players out of the game?