Saints boss Chris Boyd says he will 'monitor our numbers closely' after losing Harry Mallinder to a long-term knee injury.
Mallinder had surgery on Tuesday morning and looks set to be sidelined for the rest of the season with the knee ligament damage he sustained in the recent defeat to Clermont Auvergne.
It is a huge blow for Saints for several reasons, with Mallinder offering such back-line versatility.
The black, green and gold are already without the likes of Andy Symons, Ken Pisi, Nafi Tuitavake and Rory Hutchinson due to injury.
And with Dan Biggar heading off on international duty with Wales, the squad is stretched.
Ahsee Tuala, George Furbank and Matt Worley are the only specialist full-backs in the squad, but the likes of Andrew Kellaway, Tom Collins and James Grayson are able to play 15.
However, with injuries in other areas, those players are needed elsewhere.
And when asked whether he wants to bring in cover for Mallinder, Boyd said: "Andrew Symons is down as well, Ken Pisi has been down and Hutch (Rory Hutchinson) has been down so we've got five or six guys in that space who are all out.
"We're lucky we've got two or three young boys to step in over the next few weeks and we will monitor our numbers closely."
On Mallinder's injury, Boyd added: "Harry's a genuinely good player and generally important player for the Saints so it's a massive blow for him and for us.
"Injuries are part of life as a rugby player and you can't base yourself around one, two or any individuals.
"It's massively disappointing for Harry and for us, but life goes on for him and the Saints."