Weitering was sandwiched in a high-flying marking contest and had the full weight of WA forward Mitch Georgiades fall on his ribs and shoulder as they crashed to the turf.
But it was Weitering's head and neck that looked to be the biggest concern, with replays showing Georgiades' elbow may have made contact with the Victorian defender's head as they fell to the ground.
An out-of-sorts Weitering received medical treatment on the turf for about nine minutes and was placed in a neck brace before being stretchered off.
Victorian and WA players went over to tap Weitering to give him their support, and the 28-year-old gave a thumbs up to the crowd as he was driven off the field.
He was placed in an ambulance and driven to hospital.
"They told us it's precautionary, let's hope that's the case," Victoria coach Chris Scott told Channel 7 at quarter-time.
Saturday's match at a sold-out Optus Stadium is the first AFL Origin contest since 1999.
The concept started waning in the 1990s as clubs became more concerned about their star players getting injured in the State game.
If Weitering's injury is serious, it will be a big test to see how Carlton react, given his importance to their hopes of getting back into finals action this year.
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