The Dane, who has scored once this season and has started almost every league game in their incredible rise to second in the standings, had come on in the 31st minute with Leipzig 2-0 down.
He was forced off only 12 minutes later with a thigh muscle injury.
Leipzig, who have lost their last two league games and three of their last five, slipped seven points behind leaders Bayern Munich as they battle for a Champions League spot in their first Bundesliga season.
(Reporting by Karolos Grohmann, editing by Ed Osmond)
