Pratley was rashly brought down inside the six yard box by the last man Luke Chambers but to everyone's surprise, nothing was given.
The former Fulham midfielder described the decision as 'embarrassing' and asked why the referee didn't give the penalty after putting the whistle to his mouth.
"It was embarrassing," said Pratley.
"I'm five yards out from goal and I'm clipped from behind.
"If it's not a penalty then why didn't I shoot at goal? Why wasn't I booked? I'm five yards out and there's something wrong if I don't trust my own ability from there. I would have deserved to have been substituted if I'd missed that. It was a tap in.
"I asked the ref why he didn't give it and he said he didn't see it. Come on, please. Even the linesman could see that one, surely?
"I've watched it back on the TV and you can see the referee put his whistle to his mouth. Why didn't he blow it?
"It cost us three points and I hope it doesn't prove costly at the end of the season.''