Jack, 29, had returned from a lay-off in Rangers' past two games and has made just six appearances all season.

"He got a knock on his ankle during the game, which gave him a lot of discomfort," said Van Bronckhorst.

"Ryan Jack is a very tough player. It was definitely a foul. It is not a serious injury but the game tomorrow is too soon."

Aaron Ramsey made his debut as a substitute against Hearts but Van Bronckhorst says the on-loan Juventus midfielder "is not quite ready to start yet", while defender Filip Helander could return from a long-term knee injury against Annan Athletic in the Scottish Cup on Saturday.

"Aaron is improving each day and I think it's good to see the difference he's already made in a week, he will become better and better," explained the Dutchman.

"He will be closer to starting a game the more minutes he plays and the more sessions he has with the team."