St Kilda have reportedly offered Weitering an eight-year deal worth a record $12 million in a bid to lure the Blues' vice-captain and two-time best-and-fairest winner away from Ikon Park.
It comes with Carlton facing a fight to keep all of their biggest stars after tying Sam Walsh, Patrick Cripps, Charlie Curnow and Harry McKay to lucrative long-term deals.
The Blues have also made a bumper offer to Sydney free agent Will Hayward, in an intriguing sub-plot to the sides' blockbuster clash at the SCG on Friday night.
After touching down in Sydney on Thursday, Voss predicted Weitering will extend his commitment to the club well beyond the end of his current deal, which runs out next year.
"I'm very confident," Voss told reporters.
"I don't think we spend a hell of a lot of time in speculation, to be honest.
"He's a very important player to us ... and I'm sure at the right time we'll see him in the Carlton jumper for a very, very long time."
Weitering is central to seventh-placed Carlton's plans to stop the competition's highest-scoring attack on Friday night.
Sydney (8-1) have averaged 101 points across nine matches, spreading the scoring load with six players scoring at a rate of more than a goal a game.
The Swans' midfield is arguably their biggest weapon, led by Brownlow Medal favourite Isaac Heeney and young stars Chad Warner, Errol Gulden and James Rowbottom.
That group will lock horns with a high-powered Carlton engine room featuring Cripps and Walsh, in a battle that shapes as pivotal to splitting the sides.
"They've got a bit going for them at the moment," Voss said of Sydney.
"Clearly they're getting a lot of drive from their midfield right now and they're batting pretty deep through that part of the ground.
"They provide plenty of threats, but we still feel like there's a method there for us to be able to get after it and we can hopefully pose some questions going the other way."
Two of those come in the form of dangerous tall forwards Curnow and McKay, who have kicked 50 goals between them as the most prolific partnership in the competition so far this season.
Swans defender Nick Blakey said stopping the Blues' twin towers will be a "massive challenge" without key defender Tom McCartin, who is sidelined for a second straight week because of concussion.
"Those two boys are the best two key forwards in the game at the moment and we won't have Tommy out there," Blakey said.
"We've got full confidence in our defensive system and the way we defend as a team but no doubt we'll have our work cut out for us."
Carlton have made four changes following last week's thrilling one-point win over Melbourne, losing Adam Cerra (hamstring), Matt Cottrell (foot) and Jack Martin (calf) to injuries.
Lachlan Cowan has been dropped, while Zac Williams, Caleb Marchbank, Jack Carroll and Orazio Fantasia all return.
Sydney have brought back Braeden Campbell for Matthew Roberts (managed), while veteran midfielder Luke Parker has again been overlooked.
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