COLLINGWOOD ruckman Josh Fraser is appearing less likely by the day to take his place in Friday night's vital clash with St Kilda, with coach Mick Malthouse warning that even if the big man was selected, he was no certainty to play.

Fraser injured his posterior cruciate ligament in Saturday night's Hall of Fame Tribute match and, despite initial reports saying he could be out for a couple of months, the 26-year-old is in the mix to play against the Saints.

But Malthouse was anything but positive about the chances of Fraser getting up for the game.

"He's struggling a little bit, so we'll debate whether we'll name him to give him a chance tomorrow morning, but if we name him, it doesn't mean he's in the side," Malthouse said on Thursday.

Malthouse was more upbeat on big forward Anthony Rocca, who is fighting to beat an ankle injury.

"He looks good, and he looked good the week before. He was definite last week – there are no guarantees in football, you know that.

"We certainly hope he's a bit more advanced than he was last time, I thought he was over the line, but it wasn't to be.

"Players like that, particularly with that type of injury… he's got a screw through the bone, and I guess sometimes they pull up a bit sore the next day, so we'll cross the fingers and hope he doesn't.

"He's 30 years of age, wear and tear, the injury wasn't a good injury from last year. He works very hard, Anthony – contrary to what some people think – he works extremely hard to get right, so we're highly optimistic that he'll play."