James Roby could miss the next few weeks after he limped off against Huddersfield on Sunday.
The England hooker will have a scan on his leg to see the extent of the damage caused after only half an hour in Saints’ 17-16 loss at the Galpharm Stadium.
Saints’ coach Royce Simmons described the injury as “pretty nasty.”
He said: “It’s probably a few weeks job, but we won’t know fully until we get the scan.
“He doesn’t come off too easily, so you know you’re going to get some problems there.”