The Addicks head to Oakwell still searching for their first points of the season and are set to be without influential midfielder Jackson, who has a calf injury.
"It's a recurrence of what happened in training and we have got to get him right," said Powell.
"So I very much doubt we'll see him at Oakwell. He'll be sorely missed because he is a player that will just come up trumps with a goal.
"But it is time for others to step up. It is time for my players to stand up and be counted and my characters to really show their quality and leadership, as well as myself and my staff.
"More importantly I have to keep myself together and keep our fans together because we have a good group here. We've always wanted to add to it, and have that Championship quality and build, but if you can't you get on with it.
"The players have had the experience of last year and they need to make sure, and we all do, more importantly, that we all step up now."