Hayes injured his collarbone within seconds of the kick-off in Sunday's League Cup final after collapsing heavily in a leaping challenge for the ball.
The on-form winger joined in the celebrations after Aberdeen won the cup on penalties but his arm was in a sling which left fans fearing the worst.
And yesterday manager Derek McInnes told BBC Radio Scotland that he expects Hayes to be missing for up to six weeks, which would mean the former Inverness player could miss the Scottish Cup semi-final on April 13.
McInnes added: "We're hopeful it might be a bit sooner, but we've got to be on the safe side at the minute."