Fautua Otto will miss the start of Bristol's Championship season with a knee injury sustained while on international duty with Samoa.
The centre needed surgery following a collision in a game against Scotland in June, and is currently recovering in New Zealand.
Head coach Liam Middleton told the club website: "He is making a good recovery.
"Fautua is looking forward to being back on the pitch and he will return once he has been passed fit to fly."
The 25-year-old centre, who made 21 appearances in his debut season at the Memorial Stadium last year, should return to fitness in November.