Cornell du Preez requires "further surgery" on his larynx after taking a blow to the throat in Saturday's defeat by Wasps.
The Scotland international, 27, was taken to hospital amid concerns of a fractured larynx on Saturday and has since undergone treatment.
Du Preez lasted just five minutes of his debut, following his summer move from Pro14 side Edinburgh.
"Cornell is stable and resting in hospital," the club posted on Twitter.
"Further surgery will be required to his larynx. The club is providing full support for Cornell and his family and wishes him a speedy recovery."
What is the larynx?
The larynx is the technical term for what is often referred to as the voicebox in our throats.
