Bert van Marwijk's side have lost six league games in a row, a run that has left Hamburg second bottom in the table and speculation rife regarding the head coach's future.
At the end of November, Hamburg were 10th in the table, but a terrible slump in fortunes has intensified the pressure on Van Marwijk and his players, culminating in fan protests after last week's 3-0 defeat to Hertha Berlin.
Braunschweig have been bottom of the table for the majority of their first season back in the German top flight for close to three decades, meaning Saturday's encounter is pivotal for both sides.
Given that Bayern have not lost against Freiburg since 1996, Pep Guardiola's men will be confident of maintaining their 13-point lead at the top.
Jurgen Klopp's Borussia Dortmund face Eintracht Frankfurt hoping to boost their own chances of finishing second.
Borussia Monchengladbach can keep up the pressure on the top four when they travel north to Werder Bremen. But with no win in five in the league, Gladbach could find it difficult, despite Bremen's poor home form.
