Dylan Hartley remains a doubt for Saints' clash with Clermont Auvergne on Saturday - but James Haskell is nearing a return from injury.
Hartley has missed the past two matches due to what boss Chris Boyd describes as a 'grumbly knee'.
And it remains unclear whether he will be able to feature in next weekend's Challenge Cup clash at Stade Marcel Michelin.
If he doesn't, it appears unlikely Hartley will play for Saints again before the Six Nations as Boyd is eager to rest his internationals for the home fixture against Timisoara Saracens on January 18.
"I'm not sure if Dylan will play next week and then in the Timisoara game we'll give our international guys that off," Boyd said.
"Apart from the grumbly knee, Dylan is in pretty good nick.
"It's not ligament trouble. Maybe he's got a meniscus issue or it might just be wear and tear.
"I would have thought he'd be fit for the Six Nations but those grumbly knees can keep grumbling."
Haskell, who has made just three competitive appearances for Saints since joining the club last summer, will also miss the match at Clermont.
But the flanker is making good progress after having surgery on an ankle problem back in November.
"James chose the surgical route and he's only a couple of weeks away from a return now," Boyd said.