Gareth Barry will regain the captaincy of Aston Villa in the absence of Martin Laursen after the Danish defender was ruled out for two months.
Barry was appointed skipper of Villa by Martin O'Neill in the summer of 2006, but lost the armband when it appeared he was set to join Liverpool in the close season.
Now the England midfielder will lead the side out in Saturday's FA Cup fourth-round tie at Doncaster and until Laursen, who has undergone knee surgery, regains fitness.
Barry is one of only two survivors from the Villa side beaten 3-0 by Doncaster in a Carling Cup tie three years ago.
O'Neill said: ''To lose Martin is a real bad blow for us and a real big blow for him.
''He missed a couple of games before coming back for the West Brom match, when he felt pretty good.
''We felt that, with a bit of man-management, we could tide things over until the summer in terms of avoiding surgery, but he has had a reaction.
''He has needed an operation and we are now looking at eight weeks on the sidelines, which is a long, long time.
''He has been brilliant with us, terrific for the last couple of years since coming back from a serious injury.
''It is a major loss but it's something we will have to deal with.''
O'Neill confirmed: ''Gareth Barry will be the captain in Martin's absence and there is no problem with that whatsoever. He has done it before and he has had an exceptionally good season.''
The Villa manager is aware it is 52 years since Villa won the FA Cup, a fact he was reminded of this week following the death of Johnny Dixon, who skippered the side in the 1957 final triumph over Manchester United.
And the former Celtic boss is aware that Doncaster will test his side after watching them overcome Cheltenham in a third-round replay in midweek.
O'Neill said: ''It is a long time since we won the cup. That is a fact, but we can't be thinking of things like that because we face a difficult game.
''Doncaster are a fine footballing side and were well worth their win over Cheltenham.
''It is going to be tough for us and they will fancy their chances after beating Villa two or three years ago in the League Cup. ''But I am sure our players will be prepared for what lies ahead. They realised that we would have a tough game at Gillingham in the last round and that proved to be correct and it will be the same this time.
''It is a competition we want to progress in. I have never won it and it does mean a lot to me, the players and all the fans who will be travelling up the motorway to Doncaster.''
O'Neill will be without star winger Ashley Young, suspended following his straight red card in the 2-1 success at Sunderland last weekend.
The Villa boss has spoken to the player about his rash challenge on Dean Whitehead, but now wants to draw a line under the incident.
O'Neill said: ''It was totally unlike Ashley. It is disappointing we will be without him for three games. It has happened and I can't hold it against him for the rest of his life.''
Defender Luke Young will also be banned for tomorrow's tie after collecting his fifth yellow card of the season at the Stadium of Light.
John Carew and Wilfred Bouma are still not ready to return after back and ankle setbacks respectively.
O'Neill is hoping to fix up a behind-closed-doors friendly next week to give the pair much-needed match practice in the hope they will be able to return for the final third of the campaign.
Carew has been sidelined for two months, which has meant Gabriel Agbonlahor often being used as the sole striker.
Bouma dislocated an ankle in an Intertoto Cup game against Odense in July.