Etherington, 30, was subbed four minutes after the break having been fouled earlier by Emmerson Boyce.
Etherington later hobbled out of the DW Stadium looking furious.
Keeper Asmir Begovic,24, said: "It was disappointing, he is an important player for us and we missed him out there once he came off.
"He had a knock from the tackle in the first half. It has forced him to come off. It didn't work out for us. Hopefully we can get everyone fit and ready to go next Saturday at home to Wolves.
"We weren't really clicking on all cylinders.
"We were trying to do different things and didn't stick to our game-plan as well as we should have. When you do that you can't be surprised you didn't win the game."