Smith-Schuster, who turned 24 on Sunday, was walking off the field during the second half of the game when he unknowingly stepped on a penalty flag and appeared to tweak his ankle.
He hobbled off the field and was limited for the remainder of the game.
Head coach Mike Tomlin said Smith-Schuster wasn’t seriously injured but it could be an issue with the Steelers playing again on Thursday, ESPN reported.
The official injury was listed as an ankle/toe injury.
Ben Roethlisberger completed 32 of 46 passes for 267 yards, with two touchdowns to help the Steelers secure their undefeated record (10-0) over the Jaguars in a 27-3 victory.
The Associated Press contributed this report.