Queens Park Rangers midfielder Shaun Derry has stated that "no-one knows what the rule is" regarding which tackles constitute red card offences.

Referees' chief Mike Riley is reportedly in the process of providing further instruction on the matter, with a host of inconsistent decisions plaguing the past few weeks of the season.

"We're not clear what we can and can't do. When you look at some of the images or footage after the weekend's action some of the tackles that you think are red cards are only getting a yellow or no card at all," Derry told talkSPORT.

"There are some which you think aren't even a yellow card and the players are getting sent off. It's a grey area at the moment ... no-one knows what the rule is."

Derry is expected to be in action for the R's against Chelsea in the FA Cup tie on Saturday afternoon.