Preston manager Phil Brown has accused some of his players of avoiding physical challenges.
North End lost 1-0 to League Two Southend in their FA Cup first round replay at Roots Hall on Tuesday.
"If a player refuses to put his head in for a header he's not going to be playing for Preston North End," Brown told BBC Radio Lancashire.
"You're after a little bit of conviction in the final third and we didn't have that."
Brown added: "I'm sick to death of talking about confidence, when you cross the white line you play football."
The League One side take on Bury at Gigg Lane on Saturday and the former Hull City boss remains hopeful that he will be able to change the side.
"We've got a number of the injured lads available for the game on Saturday.
"Graham Alexander, Ian Ashbee, Keammar Daley and Jamie Proctor should all be available if they come through a training session on Thursday."