The shot stopper has been a huge player for boss Ange Postecoglou in the past 18 months.
But he has now undergone surgery after playing on with a fractured ankle in their 4-0 win against Manchester City.
Per talkSPORT, Postecoglou will trust 36-year-old Fraser Forster to see them through for the moment.
But a move for a keeper in January appears very likely, as Vicario may not be back until late this season.
Burnley’s James Trafford and Sunderland’s England under-21 ace Anthony Patterson are two transfer options, per the source.
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