MICHAEL Duff is fighting a race against time in an oxygen tank to be fit for Burnley's FA Cup third round clash with Liverpool.

The Clarets defender is spending the week undergoing specialist treatment on the calf strain he suffered during Monday's 1-0 win at Stoke City.

Burnley used the oxygen tank to good effect earlier in the season, when goalkeeper Danny Coyne spent a September week in a pressurised container to successfully shake off a hamstring injury.

And Duff must be praying for similar success since the former Cheltenham ace, who turns 27 next Tuesday, faces the unthinkable prospect of missing out on the biggest game of his career later this week.

Clarets boss Steve Cotterill said: "Michael is in the oxygen tank, but we are just not sure there will be enough time.

"Until the scan results come through, we just don't know yet if he will be fit."

Cotterill revealed that Graham Branch, who also picked up a leg injury at Stoke, is hopeful of recovering to face the Reds at Turf Moor on Friday night in front of Burnley's biggest home gate of the season.

Turf Moor officials today confirmed that 17,000 tickets have already been sold for the televised third round clash, with fans being advised to obtain tickets in advance since it is highly unlikely that cash turnstiles will be open on the night.

Meanwhile, there is further good news at last on injured goalkeeper Danny Coyne, who is set to resume full training at the end of this week.

Welsh international Coyne has missed Burnley's last 11 games since damaging a hamstring tendon in the miserable 3-0 defeat at QPR in October.

Replacement stopper Brian Jensen has been in sparkling form since, keeping six clean sheets in 11 games and three in his last four games.

Cotterill said: "Danny might start training again at the end of this week. The Liverpool game has come too early for him and anyhow, Brian has been in terrific form so we are in a healthy position there."

Elsewhere, Birmingham City target Robbie Blake was still a Burnley player this morning after his proposed £1.25m move hit a snag over agents' fees.

The Clarets have agreed the club-record sale of Blake, who has also agreed personal terms with the Premiership side.

However, Burnley are standing their ground after City asked them to help out with an unexpected payment to the player's representative.

Chief executive Dave Edmundson said: "There is a question mark over what the agent is claiming.

"The fees are higher than Birmingham expected, but as far as we are concerned that is between the buying club and the player's representative."

I understand that Burnley chairman, Barry Kilby, was set to hold further talks with City managing director Karren Brady later today in a bid to resolve the deadlock.