Carlton have hit a major hurdle after their strong start to the AFL season, with a knee injury set to sideline star forward Harry McKay for at least six weeks.
The Coleman medallist has suffered a lateral meniscus tear and will undergo surgery on Thursday.
McKay had battled knee soreness in recent weeks and was reassessed after Sunday's big win over Adelaide, which saw the Blues surge into the top four with a 6-2 record.
It is Carlton's best start to a season since 1996 - the year after their most recent premiership.
McKay has been in fine form, kicking 20.11 from eight games, and Carlton are banking on the powerful forward to re-join their finals push in the second half of the year.
"This news is obviously unfortunate for Harry, given the really strong start to the season he was having both personally and as a leader for our side," Carlton football boss Brad Lloyd said.
"Harry will have the surgery tomorrow morning (Thursday).
"He's the ultimate professional so will attack his rehab to be in a position to make an impact when he returns to the side, which at this stage we expect to be around three weeks after the bye."
McKay kicked three goals against Adelaide as fellow key forward Charlie Curnow took centre stage with six majors.
The star duo combined for 45 goals this season in a partnership that had blossomed while both of them managed to stay mostly healthy over the opening eight rounds.
"They're loving forming that combination," coach Michael Voss said after the Adelaide game.
"We rarely see them in the same contest together. They have formed a great relationship in the last little while."
In another injury blow, livewire forward Jack Martin will be out of action for one or two weeks with a calf strain that led to him being substituted out of the win over Adelaide.
Inexperienced defender Luke Parks is set for about three months on the sidelines with a bone stress issue in a foot.
George Hewett (calf) and Liam Stocker (shoulder) are expected to be available to return against GWS on Sunday.