Prop: Darryl Marfo (Scotland)
The Scotland prop was one of the finds of their autumn series but is likely to miss at least the first two matches of their Six Nations campaign. The 27-year-old has not played since emerging from obscurity to start all three November Tests but a specialist deemed earlier this week that an ongoing back problem does not require surgery, however further treatment.
Hooker: Fraser Brown (Scotland)
Fraser Brown, the Glasgow Warriors and Scotland hooker, faces a lengthy spell on the sidelines while medical specialists try to understand why he has suffered a number of head injuries over the past few months without having shown any of the usual symptoms of a concussion.
Prop: Zander Fagerson (Scotland)
Scotland prop Zander Fagerson will miss the bulk of the NatWest 6 Nations after suffering a foot injury. Glasgow, who will play Leinster in the Champions Cup on 14 January, revealed the 21-year-old would be out for up to eight weeks after an accident in training.
Lock: Jake Ball (Wales)
The Scarlets lock is likely to miss Wales’ Six Nations campaign because of injury. The 26-year-old went off in the first half of Wales’ 33-18 loss to New Zealand with a dislocated shoulder that later required surgery. Scarlets coach Wayne Pivac confirmed Ball would be sidelined from three to four months.