Rubezic played the full 90 minutes of Aberdeen’s 2-0 Scottish Premiership defeat at Hibernian on Sunday and was booked for his troubles.
Nick Montgomery’s Hibs scored goals in either half to put Aberdeen to the sword and pick up all three points.
Rubezic has won praise this season and has been linked with a number of clubs south of the border, including Ange Postecoglou’s Tottenham Hotspur.
Miller though feels that Rubezic is a raw player who needs to calm down, especially as he can lose his bearings.
The Aberdeen legend believes that when Aberdeen concede goals, Rubezic usually has some involvement.
“When the ball goes in the back of the [Aberdeen] net you can usually trace something back to Rubezic”, Miller said on BBC Sportsound.
“He’s very raw, he loses his bearings at times.
“He needs to calm himself down.
“Maybe the players round about him need to have a calming influence on him as well.”
Aberdeen sit third from bottom in the Scottish Premiership standings, but are only ten points off third placed Hearts.
They are next due to host Kilmarnock on Wednesday evening.
