Both were ruled out on Wednesday with McDonald rested following an injection to relieve knee soreness and Cameron experiencing quad tightness.

McDonald was due to play for Jack Riewoldt's Rampage side in the February 22 tournament at Marvel Stadium, with Cameron selected to play for Nat Fyfe's Flyers.

The Demons confirmed on Wednesday their player had been administered a cortisone injection to relieve patella tendonitis but is not expected to miss any other games.

Cameron is also on track to play in the pre-season series.

"Jeremy pulled up with a tight quad after training, but scans have ruled out a tear which is good news," Giants performance manager David Joyce said.

"He'll back off training this week but is still in contention to play in the first (pre-season series) game next week."

McDonald will be replaced by teammate Bayley Fritsch, with GWS co-captain Callan Ward to replace Cameron.

Their absence is the latest bad news for the much-criticised concept, following hard on the heels of Hawthorn pair Isaac Smith and Luke Breust's decision to opt out in favour of rest.

The pair will play in Hawthorn's practice match against Carlton on Thursday and have then chosen to take advantage of an AFL-mandated four-day break.

New Hawks teammate Chad Wingard (calf) is among a number of players who have dropped out through injury.

Melbourne's Steven May (hamstring), Fremantle's Joel Hamling (calf), Port Adelaide's Robbie Gray (knee) and North Melbourne's Robbie Tarrant (shoulder) were all drafted before suffering setbacks.

Australian Associated Press