Manchester United boss Sir Alex Ferguson says the Premiership's refereeing standards is affecting the injury toll this season.

"I think standards are slipping," said Fergie. "There was a conference for managers in the summer, with a promise that tackles with a raised foot would get a red card.

"We were also told that tackles from the back would get a red card. Standards must be slipping because there have been some bad tackles recently, not just in our games.

"What happens then is if someone gets seriously injured who gets the blame? The referee gets the blame."