Saints are awaiting the results of a scan on the toe injury sustained by Jon Fisher at Scarlets last Friday.
The flanker was forced off after just two minutes at Parc y Scarlets, where Mallinder’s men went on to win 24-7 in the LV= Cup clash.
Fisher, who signed for Saints during the summer after a successful trial spell, immediately applied ice to the injury and will now be hoping it does not keep him out for too long.
“Jon’s hurt his toe,” confirmed director of rugby Jim Mallinder.
“Don’t ask me too much about big toes, but he’s been for a scan on that and we’re just awaiting the results.”