Former Socceroo Mark Bosnich is on a two-week trial at the club and looking to prove that he can still perform at a high level.

But the Mariners' goalkeeping coach says earning a contract is only the first step for Bosnich. Then there's the small matter of getting into the team.

If he does sign then Bosnich would be the hot favourite to fill in for Danny Vukovic during his ban.

Once the suspension is served though Crawley said the battle for the jersey would be a fierce one - should Bosnich agree an extended stay.

It wouldn't be a straight fight between Bosnich and Vukovic with youngster Andrew Redmayne part of the Qantas Young Socceroos side.

Crawley told au.fourfourtwo.com: "In terms of goalkeeping ranks here at the club we’re probably the envy of all the A-League.

"We’ve got an Under 20 international in Andrew Redmayne, Danny Vukovic of couese and so if Mark (Bosnich) was to sign he’d have a hard task in front of him.

He wouldn’t be number one, two or three, he’d be one of three goalkeepers. It would be very competitive."