Why? He hasn't done anything to deserve selection.
To be fair, neither had Maddinson, or Cartwright for that matter. Bring back Mitch!
I hope the pitch is the almost traditional Melbourne drop-in road, and Warner, Khawaja and Smith all make first innings tons. Maybe Cartwright is being picked to open the bowling in the Paki second innings after the follow-on is enforced for the first time in years.