ADELAIDE defenders Andy Otten and Ricky Henderson have both suffered injury setbacks, which will delay their pre-season until the end of January.
Otten is recovering from minor surgery on his right knee, while Henderson has had back surgery.
The Crows said Otten's injury was not related to the ACL reconstruction, which kept the 26-year-old sidelined for the first half of the 2015 season.
"Andy had a bit of a clean-out of his knee last week," Adelaide coach Don Pyke told the Crows' website.
"Andy came back to (pre-season) training, started doing some running and his knee flared up a little bit, so we’ve taken the action there. He’s probably going to be delayed through until the end of January for a return to training."
Henderson played out the 2015 season with a back complaint, in the hope it would settle in the off-season.
However it hasn't progressed and the club decided surgery was the best course of action.
The 27-year-old is expected to resume training at the end of January.
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Despite the setbacks, the pair is expected to be available for the Crows' round one Showdown clash against Port Adelaide.
"We're pretty positive that the way they’re presenting at the moment will give them a chance to be available for round one," Pyke said.
"Once we get them back out on the track, we’re hopeful they’ll be available for enough conditioning to get ready for the start of the season."
Groin issues have hampered recruit Curtly Hampton's new start at the Crows.
The former Giant is expected to begin full training in the new year, while young Crows midfielder Brad Crouch is taking steps in his rehabilitation from a foot injury that ruined his 2015 season.
"We’re really happy with how Brad has progressed. He’s pain free, which is great," Pyke said.
"He’s mainly been doing straight-line running but now he’s into some change of direction (running). I’ve said to Brad from day one that we’re not going to rush him. It’s important we get it (his foot) right once and for all and give him the best chance to have the best year he can have.
"I’m really positive he’ll return to training sometime in January. How soon that will be, we’ll be guided by how he pulls up when we get into that change of direction running."
