Mitchell Marsh still to prove himself at No.6

Australia's selectors have a big decision to make over the next two days. Usman Khawaja is fit, and someone has to miss out to accommodate him. Joe Burns and Shaun Marsh are the two candidates. That Mitchell Marsh is not even being mentioned as a possible omission says a lot about the way the current selection panel views the role of the allrounder in Australia's Test line-up.

In years gone by, Australia often entered Tests with only four bowlers, but coach Darren Lehmann has noted that it's easy to do so when two of those bowlers are Shane Warne and Glenn McGrath. Shane Watson was a regular in the Test line-up in the years that followed, and now it is Marsh who offers what the selectors consider an important fifth bowling option.

On the bowling front, Marsh has developed a happy knack for breaking partnerships and in his past five Tests he has collected 13 wickets at 26.61. However, it cannot be ignored that Marsh bats in the top six in a Test team, yet has not managed a half-century since his debut series against Pakistan in the UAE late last year.

"There's obviously been a little bit of pressure on me to score runs," Marsh said in Melbourne on Wednesday. "I've tried not to take too much notice of it because, as a team, three out of the four Tests [this summer] we've made over 500 in the first innings, so I haven't felt under too much pressure in that sense.

"As a batsman you get paid to score runs and if you're not doing that there's going to be some pressure. That just comes with the territory of being an Australian cricketer. I'm just loving every moment of this. It's Boxing Day, it's Christmas. It's going to be a great week."

Marsh was almost superfluous during Australia's big win over West Indies in Hobart, where he took one wicket for the match and spent much of it wearing the pads, waiting for the end of a partnership between his brother Shaun Marsh and Adam Voges. The world-record fourth-wicket stand eventually ended at 449, but Mitchell Marsh got to face only 11 balls before Steven Smith declared.

"I try and keep my mind off batting when I'm waiting to bat," Marsh said. "I don't want to waste too much nervous energy. Obviously when you're sitting there all day you start to get a bit tired. Anytime you're next to bat after a 400-plus partnership it's great for the team.

"It was awesome to watch Shaun and Vogesy, two great mates, batting together for Australia. It was just really great to see. I've done a lot of waiting this summer, but that's a great thing for us. I'm happy to wait if it means we're making 500-plus runs. I'll come in at the end and try to get a few for the team."

Shaun made 182 in that innings but finds himself in a contest with opener Joe Burns to keep hold of a place in the XI, with Usman Khawaja to return after a month out with a hamstring injury. Burns was struck on the forearm while facing fast bowler Scott Boland in the MCG nets on Wednesday and left the nets with team doctor Peter Brukner to have his arm iced before returning later in the session.

Burns scored a century in the first Test of the summer against New Zealand at the Gabba but has not passed fifty since that Test, and if he is dropped the likelihood is that Khawaja would move up to open with David Warner. Mitchell Marsh said his brother Shaun was not worried about speculation over his place in the side and was in a good space mentally at the moment.

"Shaun has changed a lot as a person over the past couple of years," Marsh said. "He doesn't buy into what people say, he's just extremely focused at the moment. You can see that in his batting, he's batting absolutely beautifully. He's doing everything he can. What will be will be, I guess."