Northampton full-back Ben Foden could miss much of the Six Nations after suffering a knee injury in last week's 18-0 victory over Newcastle Falcons.
Foden, 28, played in the last two autumn Tests on the wing for England, who start their Six Nations campaign against France on 1 February.
Saints boss Jim Mallinder said Foden was expected to be out for 12 weeks.
"Ben is a quick healer so he thinks he can get back before then but you cannot rush these things," said Mallinder.
Speaking to BBC Radio Northampton Mallinder said Foden is in a "positive" frame of mind, with the coach adding "it could have been worse, it could have been better".
England already have doubts over Leicester duo Geoff Parling and Manu Tuilagi as well as London Irish wing Marland Yarde going into next year's Six Nations.
Stuart Lancaster's side play France at the Stade de France on the opening weekend of the tournament before facing Scotland a week later.