Bolton midfielder Ivan Campo is facing a spell out of action after breaking a foot in the FA Cup defeat of Arsenal.
The 31-year-old Campo suffered the injury following a challenge from Abou Diaby that saw the 19-year-old booked.
The Spaniard's absence means a selection headache for manager Sam Allardyce, who is without a number of key players.
El-Hadji Diouf, Jay-Jay Okocha, Abdoulaye Faye and Radhi Jaidi are away on African Nations Cup duty.
Gary Speed and Henrik Pedersen are recovering from knee and Achilles injuries. In addition Khalilou Fadiga missed the cup game with a knee problem.
• FA Cup hero Stelios Giannakopoulos is calling on Bolton supporters to keep the faith in all competitions.
The Greece winger grabbed the winner against holders Arsenal in front of just over 13,000 fans at the Reebok Stadium.
He said: 'The crowd was a bit of a disappointment because we were playing a big team. Maybe there were few people in because the game was on television and it was a cold night.
'But hopefully if we get a home draw in the next round then the fans will come back in numbers.'
Manager Sam Allardyce was also perplexed at why so few people witnessed his side's progress into the fifth round - the draw is made tomorrow.
'I can't understand it,' he said. 'There was no atmosphere and that does make life difficult for both sets of players.'
The sparse crowd got their reward six minutes from time when Giannakopoulos got the all important goal heading home after a cross from Ricardo Gardner.
It was his third goal in the last four meetings between the clubs at the stadium and helped Bolton complete a league and cup double this season.
Given that a number of Allardyce's squad are either away on African Nations Cup duty or injured it was a remarkable result.
Giannakopoulos said: 'It was a good performance and a great victory. Every win increases our confidence and this was a big win. The goal came because of the work we had done in training and it was a brilliant cross from Ricardo.
'We are now looking forward to the draw and the next round of the cup. We will try our best again.'
Allardyce would rather get to the cup final than finish in a Champions League place.
He said: 'That would be more important for this club and is a reachable goal for us. By beating Arsenal it tells everyone that we might be capable of doing that if the draw is kind.
'When the next round comes around we will have most of our players back from African Nations Cup duty. The stand-ins have been magnificent and a lot of teams will find it difficult to get a good result here.'
Arsenal manager Arsene Wenger took comfort in defeat from the performances of some of his young players.
He said: 'It is important we do not feel sorry for ourselves. We must take positives from our defeat and keep going. We will surprise many teams until the end of the season if we maintain this spirit.'
After exiting the Carling Cup in midweek after losing to Wigan, Wenger claimed it was 'very cruel' they lost their grip on the FA Cup.
'I thought we did enough to win the game,' he said. 'It was a match we should have won by three goals.
'We played away from home with a very young side and I cannot remember Bolton creating one chance until the moment they scored. We created plenty of dangerous situations in the second half.
'We were resolute and determined. We took over after 25 minutes and dominated the second half in the middle of the park. It is very cruel and difficult to take, losing a game like that. We have got knocked out in the last minutes of two cups.
'In the first game (against Wigan) we were always under threat of conceding a goal but not in this one.'