Ulster and Ireland centre Paddy Wallace is expected to be sidelined for six to eight weeks following surgery to repair a thumb injury.

Wallace suffered tendon damage to the digit on his left hand during last weekend's Heineken Cup clash with Clermont Auvergne.

If was initially hoped that surgery would not be required but following further assessment, the 32-year-old went under the knife.

The problem is likely to keep Wallace out of action until after Christmas while any complications could hurt his Six Nations hopes.

Ireland's first game of the tournament is against Wales on February 5.