The Scotsman has come in for some criticism about his physique since arriving in Brisbane but Farina says neither the player nor the coaching staff are concerned.

In a column for the Brisbane Courier Mail Farina said: "The criticism over Charlie's fitness levels does not wash with anybody from the Roar.

"In fact, we encourage the barbs because it will only motivate the popular Scotsman even more to prove his doubters wrong."

Farina says Miller is old enough and experienced enough to deal with criticism and it all seems water off a duck's back.

"Having been under constant scrutiny during his career, particularly during his time at Rangers, Charlie is used to being criticised and is at a stage in his career where he does not let it get to him. That's great for the Roar, because regardless of what people are saying it's not going to have a negative effect on his weekly performances," said Farina.

Miller is expected to be part of the side to face Adelaide United at Suncorp Stadium on Sunday.