Wales international and Bath lock Dominic Day is set to join Japan side Toyota Verblitz at the end of the season.
The former Scarlets second-rower, who joined Bath in 2012, has made over 100 appearances for The Rec outfit.
Bath, currently in ninth place on the Premiership table, will travel to Franklin's Gardens to face the in-form Saints side.
The 30-year-old welcomes the new challenge that awaits in the Far East.
"I've absolutely loved my time with Bath, and will be sad to leave," Day told Western Daily Press.
"At this stage in my career, I just felt the time was right for a fresh challenge, and that will certainly be the case in Japan."