The German midfielder was supposed to lead the team in the penalty shoot-out loss against Frankfurt but decided to hand it over to defender Nico Schlotterbeck before the match.
"I gave Nico the armband because I felt I haven't been in the starting lineup much in recent weeks," said the 29-year-old to Kicker after the defeat.
"For us as a team, it's important to have some continuity and a permanent point of contact. He is doing the role really well right now."
Brandt scored the equaliser for the BVB in the second half of their cup exit against Frankfurt but could not help his side in the 4-2 penalty shoot-out loss, handing his team their second defeat in all competitions this season after losing Der Klassiker derby recently.
Schlotterbeck is expected to continue as Dortmund's skipper in the absence of the injured Emre Can.
