Queens Park Rangers manager believes that Anton Ferdinand has 'dropped his standards' following the race row involving Chelsea captain John Terry.
The former Crystal Palace boss has singled out the defender along with Danny Gabbidon over their dip in form.
"[Ferdinand] has not been himself," said Warnock. "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."
Meanwhile, developments have been made in the racism controversy between Ferdinand and Terry, with Scotland Yard handing over the case to the Crown Prosecution Service.