Smith will undergo surgery on the injury early next week as he joins the swollen GWS casualty ward, which is threatening to reach breaking point ahead of next weekend's challenging trip to Perth to take on West Coast.

Ex-Fremantle utility Matt de Boer has been rushed into the Giants' 22 to replace Smith, and joins Harry Perryman this weekend as the fourth and fifth GWS debutants this year, joining former Dockers teammate Tendai Mzungu, draftee Tim Taranto and rookie Daniel Lloyd.

"He [de Boer] had an unfortunate hamstring issue at the start of the year and then his last four weeks he's started to get into some really good rhythm," Cameron said.

"He's a really good role player, he plays his role, he's hard at it, we look forward to giving him an opportunity and no doubt he's going to be really hungry.

"There's no doubt he'll definitely be down there in that front half providing that pressure. He's done that for probably eight or nine years while he was at Fremantle.

"He'll also spend a fair bit of time on-ball as well, he's got a big motor, he's fit, he can cover the ground. We're looking forward to seeing him bring that defensive side of his game and hopefully pick up the slack that Devon has been providing for a couple of years."

Smith's knee injury came after an innocuous incident on Friday morning in the Giants' captain's run, and follows vice-captain Stephen Coniglio's ankle injury from last weekend, which also required surgery and will cost the midfielder about 10 weeks.

"He's had an unfortunate accident this morning training on our captain's run which is going at about 60 per cent, he's changed direction, tweaked his knee, had a scan and looks like he needs an operation Monday or Tuesday," Cameron said.

"He's torn his meniscus, it can vary from six to 12 weeks, which is really disappointing because you don't expect to lose players the day before the match.

"It's no good losing any player especially for periods of time. 'Cogs' this week then having Devon out is not ideal. You start to lose a few numbers.

"We're really looking forward to seeing the guys who get the opportunity like Matthew, like Daniel Lloyd last week, to step up to the plate. We're going to come up against a very hungry Richmond team and we look forward to that challenge tomorrow afternoon."

Defenders Matt Buntine and Adam Kennedy are out for the season, while Nick Haynes and Ryan Griffen are still up to two months away.

Jacob Hopper and Mzungu are still roughly a month away, while Brett Deledio is sidelined indefinitely with a calf injury.

"Dev is disappointed, we're disappointed for him but we've got a game tomorrow and we look forward to the 22 taking on the Tigers," Cameron said.

"Through those injuries, some of these guys are playing maybe a little bit earlier than probably what they would have thought. You find out about players which is great and Daniel Lloyd's a great example, he's been in great form, he's been rewarded, he steps up to the plate last week, he can play AFL footy.

"We look forward to the guys getting those opportunities because they are coming thick and fast. Every team goes through it somewhere along the line and it's just our turn at the moment."