The Owls suffered their sixth loss in seven games on Wednesday night when Millwall won 1-0 at Hillsborough ant that result proved to be the final straw for Yorath.
Yorath had said after Wednesday's defeat: "I've never jacked anything in my life and it is a case of coming in tomorrow and trying to get on with things.
"We have all been in situations like this when the board gives you a number of games to turn things around, you get a result and then you get another number of games. It is like a guillotine hanging over your head."