Last season’s Premier Plate winners have already brought in Adrian Caceres, Dylan Macallister and Ahmad Elrich but the Gosford chief is anxious for someone to fill the hole created by the departure of Tom Pondeljak to Melbourne Victory.

Mariners also have to decide whether to add another goalkeeper to the squad with Danny Vukovic suspended for a lengthy spell when the A-League kicks off in August.

McKinna and his players head for Queensland later this week for friendly/trial matches against Capricorn Cougars and Whitsunday Miners respectively.

The Bluetongue boss told au.fourfourtwo.com: “We’re happy with the boys we’ve got in so far although in terms of training there’s been various people away on international duty and a few injuries.

"That makes it a bit more difficult than you’d like but overall I’m fairly happy so far.

“I’m still looking to add an experienced midfielder who can push forward in the Tommy Pondeljak mould and I’d also like a youngster to come in and complement Dean Heffernan and Adrian Caceres on the left side.

“I think that would leave us with good options to choose from and then there’s also the keeper issue. Obviously we’ll be without Danny (Vukovic) for a while but Matthew Trott is now back training again after an injury."

He added: "What I have to decide is whether we need another keeper and if so, is it a question of bringing one in on a long or short term deal. I’m not sure yet.

“As for the injured boys, Heff got a whack on the leg in his first match back from injury but should be okay. Matty Osman and Nik Mrdja are three to four weeks off getting back to full training.”

A potential candidate to fill the left-sided hole is David D’Apuzzo of NSW Premier League side APIA Leichhardt.

The former Qantas Joey and brother of Newcastle Jet Adam D’Apuzzo has featured in two trial matches for the Mariners in the last two weeks and is likely to be part of the squad for the Queensland trip if his club grants him permission to play.

D’Apuzzo’s APIA teammate, goalkeeper Matthew Nash, has also been linked with a Bluetongue switch recently.