Wales' Amos out until New Year
The 22-year-old was released from the Test squad for the end-of-year internationals on Tuesday after being injured during the second half of Wales's 8-32 loss to Australia in Cardiff.
Amos, capped 11 times, was one of the few shining lights for Wales during a thumping defeat by the Wallabies after coming off the bench.
A statement issued by Amos's club, the Newport Gwent Dragons, said he would now undergo surgery.
"Having been reviewed by a specialist, he will undergo surgery. Amos will then require a period of rehabilitation, with an expected return to play in the New Year," the statement said.
With Amos injured, Wales have called uncapped teenage Ospreys wing Keelan Giles into the squad ahead of their remaining November games against Argentina, Japan and South Africa at the Principality Stadium.