Saints boss Jim Mallinder has confirmed Christian Day has suffered a recurrence of his problematic ankle injury - and is not sure how long the lock will be out.
Day limped off after just 11 minutes of his return to action on Saturday, having previously been out for six weeks.
He replaced Rhys Oakley in the 51st minute of the weekend’s 31-30 LV= Cup defeat to Harlequins but was soon forced off, being replaced by youngster Teimana Harrison.
And it doesn’t look good for the 29-year-old, who initially picked up the ankle problem during the second half of the 24-6 win against Wasps on September 28.
“I don’t know how bad Christian Day’s injury is yet, but he certainly did the same injury so we need to look at that,” said a disappointed Mallinder.
Day returns to the sidelines alongside a host of other Saints first-team regulars, with the likes of Ben Foden, Courtney Lawes and Dylan Hartley all laid low by injury.
But Calum Clark’s recent return from a 32-week ban has been a big boost and Mallinder was again impressed by the flanker, who captained Northampton in Saturday’s defeat to Quins.
“Calum was outstanding again,” said Mallinder, who saw the player put in a fine performance on his return to action, against Leicester Tigers seven days earlier. “It was his second game back and he was everywhere, turning over the ball.
“It was fantastic for him and there were a lot of other good performances. You can pick out a lot of our players that played well and I’m pleased about it.
“It’s just that conceding those (four) tries meant that we didn’t win the game.”