Bristol flanker Jack Lam has been ruled out for three weeks with a fractured eye socket.
The 27-year-old suffered the injury in Saturday's win over Rotherham, which took his side three points clear at the top of the Championship table.
Lam only returned to action earlier this month after undergoing surgery on a shoulder problem he picked up on international duty with Samoa.
He had scored three tries in three games prior to his latest injury.
Lam is set to miss the games against Bedford and Plymouth Albion but could return in time for the play-offs, which start in May.
Fellow back-rower Marco Mama is also currently sidelined with a thumb injury.