Hosts Dortmund are in third place but seven points off the summit, with consecutive defeats to Wolfsburg and Pep Guardiola's side either side of the international break stalling their progress.
Jurgen Klopp's men have since won three games on the bounce in as many different competitions, defeating Napoli in the UEFA Champions League, downing Mainz in the league, and prevailing against third-tier Saarbrucken in the last 16 of the DFB Pokal on Tuesday.
Leverkusen are three points better off than their opponents and have won three league matches on the spin since their surprise 1-0 defeat at bottom club Eintracht Braunschweig at the start of November, which interrupted a six-game unbeaten run.
Sami Hyypia's side, like Dortmund, also progressed to the quarter-finals of the domestic cup competition in midweek with a 2-1 win at Freiburg.
Both of Leverkusen's league defeats have come on the road, while, before the defeat to Bayern, Dortmund had won all of their six home Bundesliga games, scoring 21 goals in the process.
The hosts have won four and drawn one of the past five meetings between the two sides, with Leverkusen's last success coming in a 2-0 win in August 2010.
Neither side can afford to lose if they are to keep the pressure on Guardiola's charges, who have dropped just four points in 14 league matches so far.
And Dortmund defender Manuel Friedrich, who made his third start of the season in the midweek cup success, has warned that the visitors will pose a serious threat on Saturday.
"We're up against very strong opposition and obviously the aim is to win and overtake Leverkusen in the standings," he said.
"We'll be doing a lot of analysing of their strengths and weaknesses and the coach will have his instructions for us.
"Then we've just got to give it everything we've got. Leverkusen are one of the best teams in the league."
Friedrich, who spent six seasons at Leverkusen before moving to Dortmund, is excited at the prospect of facing his former team-mates.
"(I'm looking forward to) just the game itself, really," he said.
"The reunion as well, of course. because I played alongside nearly all of them. There's going to be a great atmosphere, it's a home game for us and hopefully it'll have a positive outcome."
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.