Dortmund - who have finished in the league's top two for the last four seasons - are rock-bottom after a dreadful campaign under Jurgen Klopp.
The close-season departures of Mario Gotze and Robert Lewandowski, both to champions Bayern Munich, have undoubtedly hurt Dortmund - who visit Freiburg on Saturday - as have a string of injuries to key players.
Hummels and goalkeeper Roman Weidenfeller approached the supporters to talk with them and try to calm tensions, but it was not a pretty sight for a club so used to success in recent years.
"We know that we have 15 games ahead of us, full of fight," Hummels told the club's official website.
"Still people expect from us that we play football, not just fight.
"We know that it [our displays] are 98 per cent defined by our fighting spirit. In the other two per cent we have to get a little more relaxed so, 20 yards from goal, we'll make the right decisions."
With the numerical advantage, Klopp's side piled on the pressure, but Ciro Immobile missed two good chances late on, while Henrikh Mkhitaryan was denied by an excellent Alex Manninger save.
While Dortmund are bottom, victory against Freiburg would see them leapfrog their opponents.
New loan signing Nils Petersen scored a hat-trick on that occasion and will be out to stop Dortmund's nine-match winning streak against Freiburg, which included a 3-1 triumph in September. Adrian Ramos, Shinji Kagawa and Aubameyang all scored on that occasion.
Freiburg's last victory against Dortmund came in May 2010, with Papiss Cisse netting twice in a 3-1 success.
