The Polish star missed Tuesday’s Champions League clash against Celtic with a back problem, but is expected to be fit to face his former club at Signal Iduna Park on Saturday.
Lewandowski’s return will boost a Bayern side who are already full of confidence after their revival in recent weeks.
Saturday’s fixture is an opportunity to extend their lead in the title race and heap more misery on a Dortmund side currently in crisis.
Despite injuries to Lewandowski, Franck Ribery and Thomas Mueller, Bayern have turned things around since Carlo Ancelotti was sacked at the end of September.
Under successor Jupp Heynckes, the champions have won six games out of six. They have overturned Dortmund’s five-point advantage to claim top spot in the Bundesliga, notched up league and cup victories over RB Leipzig, and secured qualification to the knockout stages of the Champions League.
"We have taken a huge step in the last few weeks," Bayern forward Arjen Robben told Bild. "Three weeks ago, I wouldn’t have believed you if you’d told me where we are now. But we have to keep our feet on the ground."
Dortmund, by contrast, have endured a disastrous few weeks. Peter Bosz’s side have won just one of their last six games, dropping to second after defeats to both RB Leipzig and Hanover 96.
Consecutive draws against APOEL Nicosia have compounded their misery, destroying any hope of qualification from their Champions League group.
Under-fire coach Bosz, however, has claimed that he sees Saturday’s fixture against Bayern as an opportunity.
"Maybe this game is coming at exactly the right moment," said Bosz. "At the beginning of the season, people were expecting a lot from us. On Saturday, perhaps they will expect a little less."
- Aubameyang drought -
Expectations have certainly dropped dramatically in recent weeks. Just three weeks ago, Dortmund were being described as title favourites. Lose on Saturday, and they will find themselves six points behind Bayern in the table.
The crisis has coincided with a goal drought for Lewandowski’s opposite number Pierre-Emerick Aubameyang. The Gabonese striker has failed to score in his last five appearances for Dortmund.
The team’s biggest problem, though, remains the defence. Dortmund have conceded nine goals in their last three league games, leading to criticism of Bosz's tactical approach in the German media.
The Dutch coach has repeatedly defended his attacking philosophy, and this week insisted that he will stick to his guns against Bayern.
"We will not try to park the bus in front of goal, that’s not the way we play," said Bosz.
Bosz is expected to make several changes to the team which faced APOEL in midweek, with Marcel Schmelzer, Andriy Yarmolenko and Gonzalo Castro set to return to the starting line-up.
Jerome Boateng and Kingsley Coman are expected to defy injury concerns and start for Bayern, while former Dortmund defender Mats Hummels will also return to action, having been rested in Glasgow in midweek.
Like Lewandowski, Hummels will be hoping that he can deal his old club a significant blow in the Bundesliga title race with victory this weekend.