Victory have dropped six points behind the Mariners in the race for the Premiers' Plate, after successive losses to Adelaide United and Western Sydney Wanderers.

Substituted in the first half of their loss to the Reds was prolific front man Thompson, who has scored seven goals for Ange Postecoglou's side this season.

But centre-back Leijer was confident Victory's youth would come to the fore in Gosford, in what shapes to be a must-win clash for the club's Plate hopes.

Victory were also without Thompson last week when the fell to a 2-1 home defeat to the red-hot Wanderers, but Leijer noted youth team graduate Connor Pain - who scored Victory's goal - would be a dangerous proposition for the Mariners' back four on Saturday.

"Archie's obviously a fantastic player, and he's been a great player for this club. He's a big loss," Leijer said at AAMI Park on Thursday.

"But we're confident in our young boys, young Connor Pain came on the other night and I thought he was great.

"Andrew Nabbout, at the start of the season, showed what he's about, and he can turn a game on its head pretty quickly.

"So we're confident in the young players we've got, they've got a bit about them, they're speedy players and they're dangerous and we'll expect them to keep the Mariners defence on their toes."

Leijer was confident of Victory breaking a run of two matches at Bluetongue Stadium without a goal, and said he believed they were unlucky not to punish Graham Arnold's side last time out at Aurora Stadium in Launceston.

"Looking back, especially the game in Tasmania, I think we dominated," Leijer said.

"We probably should have put three or four (goals) past them in the first half, so I think we take that into the game. We take confidence out of that performance, and know that if we do our best football we can get a result up there."

On the re-signing of marquee Sydney FC player Alessandro Del Piero, Leijer said it was only a good thing for the growing Australian league.

"He's a fantastic player, and a massive name for the A-League and obviously he's enjoying it," he said.

"He's brought a lot of interest to the game in this country that maybe wasn't there beforehand. It's great to have players like him, and I hear there's players all over the world now that are really interested in coming to this league and playing.

"It's not an easy league to play in, those guys (marquee players) do find it tough, but it's great to have names like him ... good for the game in general."