The Dortmund coach branded the defender's actions 'unnecessary' after the Serbia international accosted his opponent in Wednesday's match
Late in Wednesday's game, Arjen Robben won and took a penalty kick that could have levelled the score. But the Dutchman's shot was saved, and a snarling Subotic approached his opponent, yelling into the winger's face. Reacting to the incident, Klopp lamented the defender's actions.
"The action was not necessary but not dramatic neither," the trainer was quoted as saying by Bild.
It is not the first time a Dortmund player has found himself in hot water this season. Kevin Grosskreutz was forced to plead his innocence in March after being accused of a racial slur towards Greuther Furth's Gerald Asamoah in their DFB-Pokal semi-final.
Dortmund have extended their lead over Bayern in the Bundesliga to six points, and face rivals Schalke on Saturday.