Saints' injury woes continue to increase with the news that James Haskell and Mike Haywood will not play again in 2018.
Haskell is set to be sidelined for another six to 10 weeks with the ankle problem which has blighted his season.
And Haywood could be out for even longer after sustaining a knee injury in last Friday's defeat at Gloucester, where he was making his 200th Saints appearance.
Another big blow comes in the form of Tom Collins, who fractured an eye socket at Kingsholm and will be out for four to six weeks.
Saints are set to be without a total of 16 players - four of whom are on international duty - for Saturday's Gallagher Premiership game against Wasps at Franklin's Gardens.
But centres Piers Francis and Luther Burrell, who were forced off at Gloucester, are fit to play.
Boss Chris Boyd said: "Piers is fine. He got accidentally stood on and he had significant facial cuts but no concussion. He passed his tests. He's fine, he just looked a little bit like the elephant man post-game.
"Tommy Collins fractured his eye socket so he's probably out for four to six weeks and the other one is Mikey Haywood, who has got a significant knee injury and will be out for a longish period of time.
"It was a tragedy for Mikey because it was his 200th game.
"Unfortunately, injuries are part of rugby and you can't control when they come or what they are.
"He'll be bitterly disappointed and we are as well because he's a very key part of us but that's why you have a squad and somebody else needs to stand up."
On Burrell, Boyd said: "Luther's okay. He just had a couple of little grumbles during the week that flared up.
And on Haskell, who has only been able to play three competitive games for Saints since joining the club in the summer, Boyd said: "He's had a grumbly ankle since day dot and we haven't been able to rehab it.
"They've cleaned it out last week and he'll be around about six to 10 weeks until he's ready to get back onto the grass.
Heinrich Brüssow and James Craig continue to battle concussion problems.
Boyd said: "Heinrich and James Craig are both undergoing protocols around concussion and they'll just keep going through that until they are ready to play."