Chris Boyd says Saints will be 'in real trouble' if they don't get players back from injury soon.
But the boss has praised his men for the way they have handled the huge amount of absentees this season.
Saints were missing 16 players for their trip to Newcastle Falcons last Friday but they still managed to claim a bonus-point victory, beating the league's bottom side 31-17.
It was a third successive Gallagher Premiership away success for Boyd's side.
And some of the players who featured will 'double up' as they turn out for the Wanderers in the Premiership Rugby Shield semi-final at Saracens on Monday night.
"On reputation and possibly early-season form, we're probably eight or nine players away from a full-strength 23, which is fairly significant," Boyd said.
"We've got a bunch of short-term injuries we were hoping to get back for Friday's game but we didn't get any of them.
"We've got a semi-final against Saracens for the Wandies group on Monday and there are five or six guys who played on Friday who will double up and play again on Monday night.
"We've got seven guests for that game so we're stretched.
"Unless we get some relief back soon we'll be in real trouble, but the pleasant thing for me is that when a door's opened for a young fella, generally they've stepped through it and put in a pretty good performance."
Saints called on their fifth-choice hooker against Falcons, with talented youngster Samson Ma'asi coming on to make his debut during the second half.
And Boyd said: "It was Samson's first game for the Saints and Alex Coles came on for his second game.
"They're both young guys and I'm really pleased for them.
"They're going to be part of the Saints in the future and it's much too early for them but when king and country calls, you've got to answer."