Kobel is out with an injured ligament and Witsel has an infection.
Second-positioned Dortmund are already missing Mats Hummels, Donyell Malen, Mahmoud Dahoud, Thomas Meunier, Thorgan Hazard and Giovanni Reyna.
A home win would leave Bayern an unassailable 12 factors beforehand of second-located Dortmund with 3 video games left.
Despite their lengthy casualty list, Dortmund intend to deny the hosts securing a tenth instantly Bundesliga crown.
"We want to attempt to save you that. That's the undertaking, it's the intention," stated Dortmund train Marco Rose.
The German media refers to Bayern-Dortmund fits as 'Der Klassiker' (The Classic).
Yet Bayern are chasing an eighth instantly win within the collection, having scored 30 dreams, conceding just 5.
Dortmund have winger Raphael Guerreiro returned from harm.
They hope to collectively slam the brakes on Bayern's attack, spearheaded with the aid of former Dortmund striker Robert Lewandowski who has chalked up 32 goals in the Bundesliga on my own this season.
