The highly-rated Sloane, playing in just his second AFL match, strained ligaments in his left ankle when his leg was caught under an opponent in a tackle against Fremantle on Sunday.
Compounding coach Neil Craig's headache is the fact utility Scott Stevens suffered concussion during the same game and is in doubt for the round two clash against the Sydney Swans.
The duo joins a long list of Adelaide players to have succumbed to injury in the weeks leading up to the premiership season.
Important defender Graham Johncock was withdrawn from last week's squad and will miss at least another fortnight after he fractured a thumb in the Crows' main training session.
Players to have been slowed by injury since Christmas include Brett Burton, Andrew McLeod, Bernie Vince, Jason Porplyzia, Ivan Maric, Nathan van Berlo, Chris Knights, Brad Symes and Brad Moran.
McLeod, Vince and van Berlo all played against Freo, but looked short of a run after missing significant chunks of the NAB Cup/Challenge campaign.
Porplyzia impressed in his first hitout of the year for West Adelaide in the SANFL at the weekend, but having missed so much of the pre-season with a pelvic muscle injury, may be asked to prove his fitness for one more week in the local competition.
In better news for Adelaide fans, Maric looks set to return either in place of or to back up ruckman Jonathon Griffin, while Burton and Knights will both press their claims when they join the club's main session later this week.
