North Melbourne's unlikely AFL finals push has suffered a major blow, with key forward Jarrad Waite re-injuring his calf muscle.
Waite doubts it is the sort of 10-week calf injury that has floored GWS veteran Brett Deledio, but the Kangaroos star cannot say for now when he will be back.
North have defied expectations to be in eighth spot after 12 games and Waite has been a major factor in their stunning form.
But Waite also has a lengthy injury history and he first injured the calf during the warm-up before the round-11 win over Brisbane.
He missed the pre-bye loss to Geelong and then felt a problem with the calf earlier this week when he tried some jogging and walking.
"I'm not going to really put a time limit on it - I don't think it's going to be a 10-week injury or anything like that - but really you just have to respect it," he said.
"Hopefully I play some good footy in the second half of the year."
Waite added this week's twinge was nothing as bad as the initial injury, but there were strong warning signs.
He added being frustrated about this latest setback was the worst possible response.
"If I get frustrated and I potentially do things too early, then that's when stuff can really hit the fan," he said.
"I had scans - I don't know what they mean - so the doc's told me there's something there and I will just listen to the docs."
But coach Brad Scott admitted to frustration that the injured had flared again.
"You can't shy away from the fact that when you're conservative in your approach and then you have a week off and then he's unavailable the week after, it's more than a bit frustrating," he said.
"But it's just the reality of it and with Jarrad's age and his importance to our team, it's just the prudent thing to do, to be very conservative.
"That's why it's very difficult to put a time frame on it.
"It's not a massive setback, it's just not responding the way we'd like."
Waite is 35 and has played 240 games for Carlton and North.
Midfielder Jed Anderson is set to return from a hamstring injury and Scott said he could be a straight swap for Waite ahead of Saturday night's game against the Western Bulldogs at Etihad Stadium.
"We've tried to add a layer of flexibility to our side, so we're not just limiting our replacement to a forward," he said.