James Haskell's injury woes continue with the flanker set to miss Saints' trip to Harlequins on Saturday.
The 34-year-old was set to return in the Wanderers' game against Newcastle Falcons last night but he remains unavailable due to a toe injury.
And that problem will mean he will play no part in the crucial Gallagher Premiership game at the Stoop this weekend.
Haskell has been hugely unfortunate with injuries since joining Saints last summer and has only been able to feature in five competitive matches for the club so far.
"He's still battling with that toe," said Saints boss Chris Boyd.
"He's had his ankle all tidied up and it's not too bad, but he's going through a rough time really.
"He's trying very hard to get himself back on the paddock but it (the injury) just doesn't want to come.
"He certainly won't be involved this week."
Alex Moon suffered an ankle injury against Gloucester last Sunday, with the lock forced off at half-time.
But he is not totally ruled out of this weekend's game as yet.
"It's yet to be 100 per cent determined so he'll be in a battle for the weekend and we'll leave a space open," Boyd said.
But Heinrich Brüssow, Luther Burrell and James Fish will definitely not be available as they continue to battle concussion problems.
"They are currently under return-to-play protocols and as we know they're a bit how-long-is-a-piece-of-string and they're open-ended," Boyd said.
"When they've come through their protocols and are ready to play we'll consider them for selection."
Players such as Darren Dawidiuk and Tom Wood are set to be handed a place in the squad this weekend.
And Boyd said: "There's always an opportunity for someone else so it's cometh the hour, cometh the man and there will be a lot of guys who will get a chance this week who wouldn't have expected to.
"It's a really good test for our squad depth."
Dylan Hartley will not return until the April 26 game at Newcastle Falcons at the earliest, while Andy Symons (knee), Harry Mallinder (knee), Mikey Haywood (knee), Ehren Painter (calf), Paddy Ryan (knee), Fraser Dingwall (ankle) and David Ribbans (ankle) are also currently out of action.