Timo Werner, 23, has a RB Leipzig contract until 2020, but extension talks have stalled and the Germany striker is tipped to be set to join Munich as Lewandowski’s replacement.
Last month, chairman Karl-Heinz Rummenigge outlined next season’s team.
“We’ve already completed stage one of the upheaval, the second will surely come in the summer,” said the Bayern boss.
“We have (Joshua) Kimmich on the right, (David) Alaba on the left and Suele in the middle of defence.
“In the midfield, (Leon) Goretzka has developed well with (Kingsley) Coman and Serge Gnabry on the wings,” he added.
Canadian wunderkind winger Alphonso Davies, 18, is another option. He was acquired last July in a $13 million (11.5 million euros) move from MLS side Vancouver Whitecaps.
However, young talent must bed in quickly at Bayern, where standards are high.
“We have no patience in the club and our fans have three times less. This club wants to succeed,” warned Rummenigge.
“The expectation is huge and we want to do it justice.”
Second-placed Dortmund, who play Hertha Berlin away on Saturday without key midfielder Axel Witsel, are level with Bayern on 57 points, and behind in the title race only on goal difference.
Lucien Favre’s Dortmund face a showdown at the Allianz Arena on April 6, but for Bayern a seventh straight Bundesliga crown would be a consolation prize after flopping in Europe.
Fixtures (all times 1330 GMT unless stated)
Borussia Moenchengladbach v Freiburg (1930)
Schalke v RB Leipzig, VfB Stuttgart v Hoffenheim, Augsburg v Hannover 96, Wolfsburg v Fortuna Duesseldorf, Hertha Berlin v Borussia Dortmund (1730)
Bayer Leverkusen v Werder Bremen (1230), Eintracht Frankfurt v Nuremberg, Bayern Munich v Mainz (1700)