Hawks' elite performance manager Andrew Russell confirmed on Tuesday that Jaeger O'Meara had suffered another setback after at one stage being close to returning to play.
He said O'Meara was suffering from "bone stress" in his knee.
"It's a new injury, different to what he had before," he said, referring to the injury that kept him out of the 2015 and 2016 seasons when he played for Gold Coast.
"We want him back at full fitness, which he's not. We got him to 90 to 95 per cent then new pain surfaced."
According to Russell, O'Meara's knee was settling down well and the 23-year-old was a chance to resume playing before the end of the season, however, the club would be "monitoring" that closely.
"We are really confident it will because he had four months of pain free, high-quality training in the pre-season. He felt 100 per cent and he moved as well as he ever has before.
"He took confidence out of that and we took confidence out of that, and as soon as this issue settles down we’ll get him out there and going again, and at this stage we'll be preparing him to play later in the season."
O'Meara played the first three games of the season, then missed rounds four and five. He pulled up sore after resuming against St Kilda in round six and has not played since.
The Hawks also confirmed on Tuesday that veteran backman Josh Gibson will miss up to four weeks with an adductor strain suffered in round 12 against Gold Coast, before the Hawks had their bye.
In better news for the club, half-back Grant Birchall will return on Thursday night against Adelaide after recovering from a posterior cruciate strain.
The luckless Birchall suffered a fractured jaw in the second game of the season and, after missing four games, he then suffered the knee injury in the opening minutes of the round seven clash with Melbourne.
Fellow backman Ben Stratton was almost in the running for Thursday night's clash at Adelaide Oval after missing four matches with bone bruising in his knee, but with a 10-day break to follow, he appears certain to return for the round 15 game agains Collingwood at the MCG.
