The Bavarians have lost three integral players ahead of the visit of the Gunners, including left-back Alphonso Davies, serving a one-match suspension for an accumulation of yellow cards.
In addition, ex-Arsenal man Serge Gnabry is likely to miss out owing to the hamstring problem he picked up in the first leg, while Kingsley Coman is definitely sidelined with the severe groin injury he sustained against Koln at the weekend.
Leroy Sane (discomfort) was absent from that 2-0 triumph entirely, but Tuchel is holding out hope that the Germany winger will be able to deputise for either Coman or Gnabry on Wednesday, where Thomas Muller should start in place of the other stricken winger.
The duo will no doubt be aiding Harry Kane - fresh from scoring his 15th goal against Arsenal - alongside Jamal Musiala, expected to demote Mathys Tel down to the bench for the second leg.
Well-rested midfield duo Konrad Laimer and Leon Goretzka - both of whom were on top form in North London - are also primed to return over Aleksandar Pavlovic and Noussair Mazraoui, as Raphael Guerreiro, who started in midfield on Saturday, should deputise for the banned Davies at left-back.
Tuchel should see no reason to chop and change the rest of his backline, though, as Eric Dier, Matthijs de Ligt and Joshua Kimmich shield Manuel Neuer, rested at the weekend as a precaution.
Bayern Munich possible starting lineup:
Neuer; Kimmich, Dier, De Ligt, Guerreiro; Laimer, Goretzka; Muller, Musiala, Sane; Kane