GREATER Western Sydney's injury bug has spread further with news that forward Devon Smith will undergo knee surgery after going down at training on Friday morning.

Smith tore the meniscus in his right knee at the Giants' final training session before Saturday's clash with Richmond at Spotless Stadium, and could be missing from anywhere between six and 12 weeks.

The 23-year-old missed nine games last year after having his left knee operated on early in the season, but hasn't missed a match in 2017, kicking nine goals and averaging 20.8 possessions per game playing as a small forward. 

Former Fremantle midfielder Matt de Boer has been named to replace Smith in what will be his first game for the Giants. Isaac Cumming has been added to the Giants' emergencies.

Smith joins vice-captain Stephen Coniglio (ankle), Nick Haynes (hamstring), Jacob Hopper (finger), Ryan Griffen (ankle), Brett Deledio (calf), Matt Buntine (knee) and Adam Kennedy (knee) as long-term outs at the club.

"He had an unfortunate accident changing direction and tweaked his knee, and has torn his meniscus," coach Leon Cameron said.

"Devon is disappointed and we're disappointed for him, because you don't expect to lose players the day before the match, but it is what it is, we move on.

"The positive side of it is that Matt de Boer comes into the 22 and gets the chance to wear the Giants jumper for the first time."

Full injury list ahead of round nine

Former Docker de Boer made his name as a run-with player through the midfield, and has also been used as a negating small forward with some success, and Cameron said he's expecting him to switch between both roles against the Tigers.

The 27-year-old suffered a serious hamstring injury during the pre-season, but has averaged 32.5 disposals and 7.25 tackles in his four NEAFL appearances, and brings a hard edge to the Giants side to offset the absence of Coniglio and Griffen as inside midfielders.

GWS rarely goes with a total shutdown tagger but there's little doubt Coniglio would have got first crack at Richmond star Dustin Martin, a task now likely to be shared by the rest of Cameron's onballers.

"A number of things get discussed but if you just worry about the one player, you sort of find that your system breaks down," Cameron said.

"There's no doubt that Matty de Boer will find himself in there against Dustin Martin, Trent Cotchin and Dion Prestia, I mean they've got a really good midfield.

"(Josh) Caddy rolls through there, young Shane Edwards as well, our midfield probably runs five or six players deep, and so does theirs, so we look forward to that challenge."