The 30-year-old was sent home from the Republic of Ireland camp on Thursday after damaging a hamstring in training the day before.

A scan revealed a bleed in the hamstring which ruled Duff out of last night's World Cup qualifier against Bulgaria at Croke Park and Wednesday night's clash with Group 8 leaders Italy in Bari.

However, Newcastle's medical staff are hopeful that his recovery could take seven to 10 days, and that gives him an outside chance of making the game against one of his former clubs.

The Magpies slipped into the relegation zone last weekend as a result of wins for Portsmouth and Stoke and their 3-1 home defeat by Arsenal.

They are currently two points adrift of safety and face a hugely significant trip to the Britannia Stadium seven days after they host Guus Hiddink's side.