Manager Paul Jewell hasn't gone as far to name him official club captain, but as long as the 32-year-old is in the starting line-up, he'll be leading them out.
Jewell said: "Jacko has led the team in pre-season and if he plays on Saturday, he will do the same.
"I don't want to make a big issue out of it and I think people outside the club read more into it than I do."
Jackson was the obvious choice to take the armband, having been vice-captain for the past two years.
During de Vos' long absence through injury in the first half of last season, he skippered the side, and was previously captain of Norwich City during his time there.
Jackson and Ian Breckin could soon have competition for their centre-back places, though, with Jewell still hopeful of making a fourth summer signing before the weekend.
Blackburn's Andy Todd is widely regarded as his first choice target, with his pursuit now dragging into a third month.
The clubs have been trying to negotiate a fee for some time and are believed to be getting closer.
Both Jewell and chairman Dave Whelan have hinted at a possible deal for a central defender before the Forest game comes round.
Jewell said: "We've been trying to get someone in and there might be something happening soon. You have to be patient in this game and whoever we bring in has to be the right one."
Whether any new recruit is handed an immediate starting place seems doubtful at this stage.
The manager says that he already knows his preferred XI and has been busy in training this week fine-tuning the tactics for Forest's visit to the JJB.
He is playing his cards close to his chest, but close season captures Per Frandsen and David Wright look certain to start while Lee McCulloch is expected to get the nod over Alan Mahon on the left side of midfield.
Jewell said: "I know the team which all being well will start the game on Saturday.
"Things could change – you can get injuries and illnesses – but that is the good thing about my squad here.
"I'm happy with most of it apart from the centre-back positions, and if I needed to bring someone into the team, that wouldn't weaken us. That's a great advantage to have and I think we've got a really good squad overall."
Meanwhile, Latics have taken delivery of their new black away strip and will wear it for the first time at Millwall next Tuesday.
Jewell and his coaching staff sported it at yesterday's official team photo shoot, and replica kits are expected to go on sale later in the month.