The Sky Blues told au.fourfourtwo.com the 20-year-old will miss the start of the season after dislocating his right knee when he slipped during the production of a virtual promo for the A-League broadcaster.

During the shoot, the Young Socceroo was juggling a football between his hands and at one point leapt out to grab it before it reached the floor, according to a report in the Sydney Morning Herald.

The promising striker, who was wearing metal studs at the time, lost his balance and injured his knee in the fall.

Fellow attacker, Joel Chianese, could be the one to step into the breach and says he's feeling the best he ever has.

''It's just an unfortunate injury (for Gameiro)], one of those things that you don't expect to happen,'' Chianese told the newspaper.

Referring to the competition for spots in the attacking third, he added: ''Once you do get your opportunity, you have to do what you can to keep it because, if you lose it, you might be out for a long time because we have quality players all around the field.''

A regular in Sydney FC’s preseason build-up, Gameiro’s absence will be keenly felt by coach Frank Farina.

The harbour-siders beat off interest from other A-League clubs to secure the former Wollongong junior on a two-year-deal.

Gameiro signed with English club Fulham in 2009 and had loan spells at Hayes & Yeading, FC Eindhoven and Wellington Phoenix before joining the Sky Blues.

But fans may have to wait until round five when Sydney take on arch rivals Melbourne Victory at Allianz Stadium to get their first glimpse of the striker in action.