Matthew Kreuzer will be restricted by a moon boot for up to six weeks, Carlton's head of football Andrew McKay says.
Kreuzer has been ruled out until at least the early rounds of the season after scans revealed a hairline fracture to his fifth metatarsal.
The 200cm big man suffered the injury after "an unfortunate movement of the foot" during an intra-squad match on Thursday and is expected to be in a moon boot for four to six weeks.
Carlton opens the season against Richmond at the MCG in just over six weeks on Thursday, April 2.
Carlton Injury Update: Kreuzer
The setback comes after Kreuzer played only one game last season due to a fracture to a different part of his right foot.
But McKay said Kreuzer's injuries could be connected and conceded the former No.1 draft pick might face longer than six weeks out given his history.
"It will just depend on how long it takes for that bone to heal," McKay said.
"Best case scenario will be four weeks, and we wouldn't scan it until after four weeks. We're hoping worst-case scenario will be six (weeks).
"It's not in the same spot that his previous fracture was. It's along the bone a little bit and it's a very stable fracture.
"It's in a different spot, so whether they're connected or not I'm not exactly sure … you would expect there's some connection there.
"(He's) very frustrated and very disappointed as you can imagine."
Kreuzer's first went under the knife to repair a foot fracture at the end of 2013 when he had a screw inserted.
But he was forced to have the screw removed and a plate inserted after the issue flared up following the Blues' round one loss to Port Adelaide last season.
The 25-year-old did not play again in 2014 and has only played 63 of a possible 115 games since his second season in 2009.
Despite Kreuzer's latest setback, McKay remained upbeat the important ruckman could return to his best.
"We're still very confident. He's had a really, really good pre-season and is probably the fittest he's been in a long, long time," McKay said.
"Obviously he hasn't played much footy in the last two years (18 games), but he's probably fitter than he was prior to that.
"So we're pretty confident that once he gets fit again there's no reason why he should have any problems with it again."
McKay said the Blues would insert a "stiff orthotic" in Kreuzer's boot and apply extra tape to his foot for added support when he returns.
In the meantime, Cameron Wood, Robert Warnock and pinch-hitter Levi Casboult will shoulder the ruck duties – starting with the Blues' first NAB Challenge match against West Coast in Mandurah on February 27.
"We've got a number of options we can use and we're confident Matthew will be back early in the season anyway," McKay said.