Saints have been dealt a blow with the news that David Ribbans is set to be out for 'a few weeks' with an ankle injury.
Ribbans was named in the team to face Bristol Bears at Franklin's Gardens on Saturday afternoon, but he was forced to withdraw.
Api Ratuniyarawa stepped into the starting line-up, with James Craig taking his place on the bench.
Saints went on to lose the Gallagher Premiership game 26-24 as Piers O'Conor scored a try deep into added time and Ian Madigan slotted the match-winning conversion.
And after the match, Saints boss Chris Boyd spoke about Ribbans' absence.
"We trained pretty well all week but we had a bit of a setback with David Ribbans suffering an injury.
"Unfortunately, he has got an ankle injury that is going to keep him out for a few weeks."
Ribbans now looks set to miss some big games as Saints face Saracens in the Premiership Rugby Cup final at Franklin's Gardens on Sunday before travelling to local rivals Leicester Tigers for a league match five days later.
Saints go to Clermont Auvergne for the Challenge Cup quarter-final on March 31 before hosting Gloucester and travelling to Harlequins during the first two weekends of April.
Courtney Lawes is already out with a calf injury, meaning Ratuniyarawa, Alex Moon, Alex Coles and James Craig are set to have to share the workload in the coming weeks.