WESTERN Australia's captain Dom Sheed has suffered a broken collarbone, prematurely ending what was otherwise a best-on-ground performance against Vic Country.

Sheed is expected to miss six to eight weeks with the injury, which occurred in a crunching bump during the dying stages of WA's three-point win at Simonds Stadium.

The midfielder collected 29 possessions and booted four crucial goals in the contest, and was the difference between the sides.

"It came in that last clash when he put his head over the ball and helped WA kick one of the final goals," said WA state talent manager Raff Guadagnino.

"I think he's left on good terms, as the leader of the bunch. We asked him come out and show his leadership and he definitely did that today."

Sheed started the NAB AFL Under-18 Championships in terrific form before a quieter showing against Vic Metro in round three.

He bounced back to lead his state to an unlikely win against Vic Country.

"Dom's been a good player for us since he was 16. Now he has a profile, he's embraced that and has learned to lead by example and deal with it," Guadagnino said.

"He probably had a shaky game against Metro but it just shows you [to] his credit that he won't have two bad games in a row."

Highly-rated WA midfielder Blake Acres suffered a popped shoulder but played on, while key forward Jonathon Marsh injured his ankle but also returned to the ground.

Follow AFL website reporter Callum Twomey on Twitter at @AFL_CalTwomey