Saints prop Alex Waller has suffered an injury setback.
Waller was due to return early in February after breaking his arm during the December 1 defeat to Newcastle Falcons at Franklin's Gardens.
But the 28-year-old's recovery has taken longer than first anticipated and he is now set to be sidelined for a couple more weeks.
"Unfortunately for Alex Waller, he's not quite ready to play this week," said Saints interim head coach Alan Dickens.
"He's been to see the specialist and he needs a couple more weeks for the healing process to be successful.
"He's absolutely desperate to play.
"You know the character of Alex Waller - he's a fantastic servant, a good player and someone who is a positive influence around the place.
"He's desperate to get back on the pitch to show us what he can do."
Campese Ma'afu and Francois van Wyk are set to continue to deputise in the absence of Waller when Saints host Sale Sharks on Saturday (kick-off 3pm).
Sale suffered a late 33-32 defeat at Bath last weekend, while Saints endured similar agony, conceding a last-gasp try as they lost 31-30 at Exeter.
And Dickens said: "Sale are a tough side, quite innovative and it's a testing game.
"They're coming off a similar result to us, going away from home and losing in the last minute or two.
"They will be hurting and they'll want to come down here and make a point.
"But we're back at the Gardens and we want to put in a good performance."