"There are a lot of players looking to see what West Brom can do for them rather than the other way round," the Baggies boss said after the 3-0 defeat at Selhurst Park.
"We have got to get back to competing. That performance and the way of going about a football match was unacceptable.
"Training last week was symptomatic of the way we played. You can't turn it on like a tap but that is what we attempted to do.
"Palace had two good chances before they even scored. We were soft, we were second to the ball all over the show.
"It was our worst performance and I don't see how we can look for any silver lining in that cloud. That was the worst because, while we've had some really bad results since I have been at the club, we have always given it our best and been committed.
"That wasn't the case today. Our defending was scandalous. Crystal Palace did everything better than us."