Uncertainty continues to surround the immediate playing future of injured Carlton star Charlie Curnow, with the AFL club unable to put a timeline on his return to the field.
Blues coach David Teague told reporters on Saturday that it was possible Curnow could miss the first half of the season after dislocating and breaking the same patella late last year.
"Possibly, we don't know," Teague said.
"We've just got to wait and see how it sort of recovers.
"It's a different injury, it's sort of two injuries - one after the other - and the recovery time is not certain.
"I'll be honest, I don't spend too much time thinking about it at the moment.
"They're (the club's medical staff) not sure and (when) they are sure, they can give me a little more clarity then."
The 23-year-old had an operation in November to fix a broken patella in his right knee suffered when he slipped on some tiles.
He sustained ligament damage in the same knee in a round 15 win over Fremantle last year and didn't play again. He also dislocated his right patella while playing basketball with friends in October.
Carlton ruled out round one as a goal for Curnow's return in January, and Teague admits he still doesn't know when the young forward will even resume training.
"I haven't asked, I'm not sure, they'll tell me when he gets closer to training," he said.
"He's not training at the moment, so until he starts getting into the rehab grab group that are doing football work that are about to transition in, that's probably when I'll probably take a bit more interest."
In better news, Harry McKay and Mitch McGovern are on target to take their place in the Blues' attack when they face Richmond in the premiership season opener at the MCG.
McKay is winning his battle with groin soreness and McGovern is enjoying a much better preparation after dealing with ankle surgeries and a broken back last pre-season.
The former Crow missed four games in the back-end of the season as he completed an intense training block to drop weight and regain match fitness.
"Last year he had a couple of injuries and this year he didn't," Teague said.
"So he was able to get some training in in the off-season and turn up to the football club in good condition."