The Collingwood premiership player has joined West Coast for the 2013 AFL season and showed encouraging signs in his debut for the Eagles in the NAB Cup against Fremantle on Saturday night, but now could be in doubt for Round 1 after his accident.
Wellingham was bouncing on a trampoline and managed to somehow hurt his ankle, and now has been diagnosed with ligament damage that will mean he will likely miss the rest of the NAB Cup and could miss the Round 1 western derby with Fremantle.
The 24-year-old will now miss West Coast's next NAB Cup game in two weeks time against his former team Collingwood.
West Coast assistant coach Scott Burns remains confident that Wellingham will be right to play in Round 1 of the season proper.
"I was in there today when the doctors were talking to him and it's disappointing for everyone, but we have to move on and it presents an opportunity to somebody else throughout the NAB Cup," Burns told Perth radio on Monday night.
"We are still aiming for Round 1 with Sharrod though. I guess you find out at the four or five-day mark with ankles usually, though, to really see where it's at."