STAR Sydney Swans prospect Nick Blakey will miss the Allies' opening game of the NAB AFL Under-18 Championships with illness.

Blakey, who some recruiters believe is worthy of a top-five pick at this year's NAB AFL Draft, has been grounded by a viral infection and will sit out the Allies' clash with Vic Country on Saturday.

It follows Blakey also missing the recent trial game for the Allies due to bone bruising, and comes on the back of last season when he wasn't able to complete the Allies' carnival after suffering a back stress fracture.

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Blakey is all but certain of costing the Swans their first pick at November's national draft after he informed the club last month he intended to join them through their Academy program.

He also had the option of nominating as a father-son with North Melbourne or Brisbane, with his father John a champion at the Roos and Fitzroy. John is now a long-time assistant coach with the Swans.

Blakey, a rangey 195cm forward who hopes to play in the midfield in the future, showed his talents for the Swans Academy during the Academy series earlier this year when he kicked 12 goals in the opening two games and finished second in the voting as the best player of the carnival, behind Tasmanian talent Tarryn Thomas.

Thomas will line-up for the Allies on Saturday, in a game that has been moved from Spotless Stadium to Blacktown due to weather concerns. The starting time has also been changed from 10am to 10.30am.

Country will be led by excellent midfielder Sam Walsh, who shapes as a No.1 pick contender after a consistent season, while possible Geelong father-son Oscar Brownless has also been named for Country.

Allies v Victoria Country, Blacktown, Saturday, 10.30am AEST  

Allies
B:
25 Ryan Gilmore, 44 Caleb Graham, 11 Keidean Coleman
HB: 8 Baxter Norton, 48 Dirk Koenen, 18 Lachlan McDonald
C: 20 Fraser Turner, 10 Chayce Jones, 28 Matthew Green
HF: 19 Bailey Scott, 31 Connor McFadyen, 12 Mitchell O’Neill
F: 16 James Peatling, 37 Jacob Koschitzke, 9 Blair Rubock
Foll: 40 Kieren Briggs, 26 Thomas Green, 46 Tarryn Thomas
I/C: 36 Matthew McGuiness, 47 Nicholas Baker, 13 Ethan Jackson, 45 Jack Tomkinson, 23 Michael Mummery
Emerg: 35 Joshua Rayner, 7 Jesse Quint

Victoria Country
B: 31 Brock Smith, 37 Dane Hollenkamp, 26 Matt McGannon
HB: 15 Lachlan Ash, 25 Kyle Reid, 6 Laitham Vandermeer
C: 10 Zac Foot, 19 Sam Fletcher, 27 Zane Barzen
HF: 30 Oscar Brownless, 14 Sam Flanders, 3 Toby Bedford
F: 8 Ned McHenry, 35 Hudson Garoni, 13 Thomas Berry
Foll: 29 Bailey Williams, 4 Jye Caldwell, 2 Sam Walsh
I/C: 39 Connor Idun, 5 Xavier Duursma, 18 Mitchell Riordan, 12 Caleb Serong, 28 Bailey Schmidt
Emerg: 7 Jai Taylor, 36 Riley Bowman