They might not have been as bad as the scoreline suggested but Johnson has handed each of the players a DVD of the match and wants them to reflect on their performance.
He told the club's official website: "They need to see what they have done to affect the game, either in a negative or positive way. I'll ask them to look at what they have or haven't done and assess themselves.
"They need to ask themselves if they could have done any more. Hopefully they'll be honest enough to see where they have gone wrong and come to me and say 'sorry, I shouldn't have done that'.
"Those who have not quite performed need to say 'sorry, I didn't affect the game as I should have done'. They need to know why we went to West Brom and lost 4-1. Some of them just haven't done enough. They were out there but they didn't affect the game."