QPR manager Neil Warnock feels that Anton Ferdinand has not played to his potential since their game with Chelsea.
Ferdinand has been at the centre of a storm concerning alleged racist comments made by John Terry during that game.
The Crown Prosecution Service are now considering whether to bring charges against Terry after files over the incident were passed on by the police.
In their four following games, QPR have lost three and won just one, conceding 10 goals in the process.
Warnock feels Ferdinand and his defensive partner Danny Gabbidon are to blame for some of their recent defeats and is asking the pair to improve.
He said: "He (Ferdinand) has not been himself. I have had words with him and Gabbidon as I think both of them have dropped their standards in the last two or three games.
"I think if they were at the top of their game, we would have beaten Man City and Norwich and had a few more points on board.
"I hope they get back into the swing because they've had a good season so far and they're both good players.
"But they have to work hard to stay at that level and I hope that a good week's training will see the benefit of that against West Brom."