The giant defender was charged by The FA earlier this month for using violent behaviour after a clash with Stead during his side's 4-3 defeat to Blackburn.
Knight appeared to head-butt Stead as both players ran upfield although the incident was not noticed by referee Mike Dean.
The flashpoint was caught on television pictures clashing with Stead and The FA decided to act.
Knight will now miss Fulham's remaining three games of the season and the news will be a blow for Cottagers boss Chris Coleman as they continue their push for a place in Europe.
Meanwhile, Coleman has played down reports linking the club with a move for the PSV Eindhoven ace Mateja Kezman.
The player's agent had claimed that Fulham were one of the sides leading the chase for the striker, but Coleman insists they have made no bid for the player.
"I don't know what has been said about a realistic bid because there hasn't been a bid," Coleman told Sky Sports News. "He is a good player and his track record says that.
"We are interested in a lot of players, but we haven't bid for any, we've had no contact with PSV over Kezman. I have seen him play lots of times, he's hungary for goals and he's a good player inside the box.
"I have certainly not made any bids for anyone even though there's a lot of players we are looking at."
