We have ended up having repetitive injuries here. That is a big concern for me.Steve Cotterill
Without revealing specific details, Cotterill says he has several new injury concerns in the wake of the Wolves defeat on Monday.
"Injury-wise it's not very good at the moment and we've a few missing, but they are not ones that you will know about until Saturday," said the Blues boss.
"Things are so stretched that I may need to look into the Under 23s for a role going into this game."
Cotterill also offered updates on several other players; including Maxime Colin (hamstring), Jason Lowe (hamstring), Craig Gardner (calf), David Davis (knee) and Isaac Vassell (knee).
Tomasz Kuszczak missed the Wolves fixture due to a groin issue that he has bee troubled with for a number of weeks.
And Harlee Dean will be missing against Fulham, due to suspension.
"Maxime is coming along, but he is not in full training yet, so it is too early for him this week," said Cotterill.
"Jason and Craig are back in training but it's about how much training they have done after quite long injury lay-offs - that's the problem.
"We have ended up having repetitive injuries here. That is a big concern for me.
"We are looking at those and monitoring those, none of them would be fit to start at this moment in time.
"David Davis has managed to get a few more days training under his belt
"Davo is not as far behind as where Craig or Jason would be, just simply because he has only missed that one game.
"The game the other night against Wolves came a little bit early for him because of the amount of training he had done going into the game.
"Isaac Vassell is on the mend, but it's slow progress.
"He's without his crutches which is nice for him, but not anywhere near being back with the team.
"He's next season now. He won't be back this year and even if he gets back in training in the last month of the season he won't be playing because that reconstruction won't be rock solid until next year anyway."