With leading scorer Steven Fletcher ruled out for the season with ankle ligament damage, O'Neill is short of options in attack but in no rush to turn to Wickham.
O'Neill said: "I'm not so sure that any player at this club could ever say they have not had a proper chance. What you have to do is produce.
"Talk to any player in the dressing room, they wouldn't say they have not had a chance. They have to go and do it. It's not true.
"You'll have to check the games he has played? Against Bolton Wanderers in the FA Cup ... Middlesbrough I'm not so sure. I go back to my statement, there's not any player here who can say they have not had a chance."