Ken Pisi will definitely miss Saints’ game against Castres on Friday night with an ankle injury.
The Samoan wing picked up the problem in Saturday’s 30-19 win at Exeter, being replaced by Luther Burrell in the 60th minute.
But Pisi could be fit in time to return in time for Saints’ trip to Glasgow a week on Saturday.
“Ken Pisi is going to be out for a week or so, he’s got an ankle injury and hopefully it’s not too bad,” said Northampton boss Jim Mallinder.
Saints will also be without Brian Mujati for the Castres clash as the prop continues to struggle with a calf injury.
Mujati missed the win at Exeter and is set to stay on the sidelines for a few weeks more.
“Brian Mujati is still coming back from his calf strain but how many weeks, we don’t quite know.”
But there is better news on James Wilson, Christian Day and James Craig as Mallinder added: “James Wilson is close, Christian Day is close, James Craig is close.
“That’s really positive news so it will be great when we can get them back.”