The Australian striker is in "great spirits" after finalising his move to the Toon and is ready to give his all at the Asian Cup.
He reportedly told friends he intended to withdraw from Australia's Asian Cup squad, feeling unable to offer the 100 percent commitment required.
The national coach spoke at length with him to get him to change his mind, and while he has not made clear his plans beyond the Asian Cup, Arnold believes he could play at the World Cup.
Australian coach Graham Arnold: "It's one step at a time for Mark. What we're concentrating on now is getting Mark fit for Oman (on July 8) and the tournament.
Australian coach Graham Arnold: "It's one step at a time for Mark. What we're concentrating on now is getting Mark fit for Oman (on July 8) and the tournament.