Exeter Chiefs centre Sireli Naqelevuki will be out for at least a month after breaking his arm in the 24-19 loss to Gloucester on Saturday.
The powerful 31-year-old Fijian has enjoyed a good start to the season and is the club's joint-top try scorer.
"He's going to be out for at least four-to-six weeks if it's a regulation break," head coach Rob Baxter said.
"If it's anything worse than that then, that time lengthens," Baxter added to BBC Radio Devon.
But Baxter says there are more than enough suitable replacements to come in for the Fiji international.
"Injuries happen in rugby and you've just got to get on with it.
"Josh Tatupu came on and did fine, Jason Shoemark has played a lot of 12, we've got Nic Sesteret, Mark Foster, we've got plenty of guys we can move in there.
"Obviously you want all your players fit, and Sireli's a great player, I'm not going to run away from that, but one man doesn't make a team. We've just got to move on," Baxter said.