Saints have been dealt a huge injury blow with the news that Harry Mallinder is set to miss the rest of the season with a knee injury.
Mallinder had surgery on Tuesday morning after suffering ligament damage in the defeat to Clermont Auvergne earlier this month.
The full-back was involved in a big collision in just the third minute of the Challenge Cup clash at Franklin's Gardens.
And though he tried to battle on, he was eventually forced off just two minutes later.
Mallinder was sent for a scan last week and that prompted this week's operation.
"Harry's operation is today and he's got a significant knee injury," said Saints boss Chris Boyd at Tuesday afternoon's media session.
"It depends what they find when they go in there but he's probably doubtful for the rest of the season."
Mallinder took to Instagram on Monday night ahead of his operation.
The 22-year-old posted: "Operation #7 in the morning.
"I'm devastated, but it's an opportunity to become a better player and person.
"I'm grateful to have such good people with me on my journey, thank you for all your continued support."