The 17-year-old midfielder from West Perth did not travel with the WA squad to Launceston for Sunday's round one clash with Tasmania due to a shoulder injury.
WA is already without the services of Jesse Hogan (Melbourne) and Jack Martin (Gold Coast) who have already been selected by AFL clubs via the Greater Western Sydney trade incentive rule.
WA captain Dominic Sheed believes his depleted side still packs the quality to challenge for the title.
"We're going to try our best," Sheed said before the team left Perth.
Originally from Kalgoorlie, Sheed has already played seven senior matches in the WAFL for Subiaco.
The smooth-moving, left-footed midfielder said being the senior player within the side came with some added expectation.
"There's a bit of pressure that comes with it, but it's a really good opportunity. I'm looking forward to it."
Sheed has been likened to Simon Black, and has averaged 15 disposals and kicked two goals in his senior WAFL appearances.
WA's vice-captain Patrick Cripps is the third cousin of current West Coast Eagle Jamie Cripps.
The East Fremantle product is a 190cm midfielder who has grown 20cm in the last two years.
"In the state 15s I was the smallest in the team so I've grown a fair bit," Cripps said.
Cripps' size and prowess as an inside midfielder has seen him likened to the reigning Brownlow medallist.
"I've been told I play like Jobe Watson, obviously not as good. But it's a complement to be compared to him," he said.
WA has not won the Under-18 championship since 2009 but did win the Under-16 national title last season with Bradley Walsh winning the Kevin Sheehan medal as the best player at those championships.
From that side, Walsh, Clem Smith, Jermaine Miller-Lewis, Matthew Ah Sui, and Alec Waterman are all in the Under-18 squad.
Walsh, Smith, Miller-Lewis and Ah Sui were all AIS-AFL Academy squad members in 2012. Waterman is the son of West Coast dual premiership player Chris Waterman.
