The Chilean was controversially left out of the team for Arsenal's Premier League trip to Anfield on Saturday following reports of a training ground bust-up.
However, the club's top-scorer returns to the side this evening in a centre-forward role as Olivier Giroud drops to the bench for the Gunners.
It is one of four changes made by Wenger as Arsenal look to pull off a miracle comeback against the German giants following their 5-1 defeat in the first leg.
Aaron Ramsey is amongst those to return to the side, making his first start since January, while Theo Walcott and cup goalkeeper David Ospina also come in as Francis Coquelin, Alex Iwobi and Petr Cech drop out.
Mesut Ozil makes something of a surprise appearance on the bench having been ruled out by Wenger earlier this week, with the German having recovered from a recent illness to make the matchday squad.
Arsenal must become the first side to ever recover a four-goal first-leg deficit in the Champions League if they are to avoid crashing out in the last 16 for a seventh successive season, but they come up against another strong Bayern Munich XI tonight.
Robert Lewandowski will once again lead the line having scored 37 goals in 38 games for club and country this season.
Arsenal: Ospina; Bellerin, Mustafi, Koscielny, Monreal; Ramsey, Xhaka, Walcott, Oxlade-Chamberlain, Welbeck; Sanchez
Subs: Cech, Gibbs, Gabriel, Coquelin, Ozil, Lucas, Giroud
Bayern Munich: Neuer; Rafinha, Hummels, Martínez, Alaba; Alonso, Thiago, Vidal; Robben, Ribery, Lewandowski
Subs: Ulreich, Costa, Bernat, Muller, Coman, Kimmich, Sanches
Follow all of the action from the Emirates Stadium courtesy of Sports Mole's live coverage of the game.