Cusiter has had a wretched run of injuries playing for Scotland

Cusiter was told he may miss the whole tournament after dislocating a shoulder and damaging ligaments in November.

But head coach Frank Hadden told BBC Sport: "Chris has recovered remarkably well and is in tremendous shape.

"Chris has exceeded all expectations and is absolutely raring to go. He has not been ruled out yet."

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With fellow scrum-half Mike Blair sidelined with shoulder damage, Gloucester's Rory Lawson was tipped to start the tournament for Scotland.

However, Hadden may get a boost if Cusiter turns out for the Border Reivers against Newport Gwent Dragons on Friday.

"We are monitoring the situation very closely and we have a few more days before we make up our minds on the starting line-up," added Hadden.

Cusiter's latest injury setback came after being tackled off-the-ball and twisted to the ground by the Pacific Islanders' flanker Viliami Vaki at Murrayfield.

Jason White, Allister Hogg, Simon Webster and Nathan Hines are definitely missing for the Twickenham clash.

But Hadden remains upbeat about his team's Six Nations chances.

"We have a top quality side," he continued.

"People point to our injuries but I'm delighted with the players that have come in.

"There is nobody in this camp that is not capable of playing at the very highest level."

Scotland finished third in last year's tournament, winning against France, England and Italy, while they lost out on their travels to Wales and Ireland.

"We must focus on continuing to make progress and I'm confident we can do that," said Hadden.