Brown is almost one month removed from a partially torn left calf muscle that occurred against the New England Patriots on Dec. 17, forcing him to miss the final two games of the regular season.
Sources told ESPN's Dan Graziano there are lingering concerns about Brown's calf holding up in the cold weather at Pittsburgh's Heinz Field, but the receiver participated in Saturday's walk-through and also was a full participant in practice on Wednesday and Thursday.
Steelers coach Mike Tomlin said Brown missed Friday's practice because of an illness, but he expected him to face the Jaguars.
Brown's teammates have maintained for several weeks that they believe he will be back for the playoffs, and Tomlin said he had seen enough out of Brown's two practices.
"I think we've all seen Antonio play enough that we know what he's capable of," Tomlin said Friday.
Brown led the NFL with 1,533 receiving yards, despite playing in only 14 games, and ranked fourth with nine receiving touchdowns in 2017. He was the league's only unanimous All-Pro this season.
He was officially listed as questionable on the injury report.