Speaking to the Official Club Website of the defeat and the poor performance given, Keane said: "It's unbelievably disappointing to finish the season like that.
"We wanted to go out on a high and our home form has been pretty decent but what could have gone wrong, did go wrong.
"The first goal was a really bad goal to give away and after going down to 10 men, we never looked like getting back in the game.
"It was very disappointing for Tom obviously, getting the red card. I had no complaints over the first booking but he got the ball for the second and sometimes you are looking for the referee in those situations to help you out but he didn't. He's a good lad though and he will bounce back.
"I looked around at the end and we looked a small team compared to Sheffield. We need big physical men and it makes me appreciate the challenge we have here and the job I have and that job starts today."